0000950170-22-022606 | 10-Q | XBRL Viewer | Apellis Pharmaceuticals INC

Marketable Securities - Schedule of Amortized Cost, Gross Unrealized Holding Losses and Fair Value of Available-for-Sale Debt Securities by Type of Security (Detail) - U.S. Government-Related Obligations [Member] - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Available for sale securities:
Amortized Cost	$ 124,746	$ 60,357
Gross Unrealized Holding Gains		3
Gross Unrealized Holding Losses	(382)	(2)
Fair Value	$ 124,364	$ 60,358

Fair Value Measurements - Schedule of Financial Instruments and the Related Fair Value Hierarchy of the Valuation Techniques Utilized (Detail) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	$ 540,297	$ 598,833
Money Market Funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	540,297	598,833
Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	540,297	598,833
Level 1 [Member] \| Money Market Funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	$ 540,297	$ 598,833

License and Collaboration Agreements - Additional Information (Detail)			1 Months Ended					3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Nov. 30, 2020 USD ($)	Oct. 27, 2020 USD ($)	Apr. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Aug. 31, 2021 USD ($)	Jun. 30, 2021 USD ($) Program	Jan. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) License	Sep. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) License	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue								$ 22,056,000	$ 5,650,000		$ 52,759,000	$ 6,273,000
Swedish Orphan Biovitrum AB (Publ) [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development cost reimbursement		$ 80,000,000.0
Non-refundable Upfront Payment		250,000,000.0
Collaboration and License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development cost reimbursement														$ 80,000,000.0
Contract research and development expense											80,000,000.0
Collaboration and License Agreement [Member] \| License [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment														$ 250,000,000.0
Collaboration and License Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment		250,000,000.0
Milestone payment received for achievement of regulatory development milestone			$ 50,000,000.0
Development cost reimbursement		80,000,000.0
Development cost reimbursement received				$ 20,000,000.0			$ 25,000,000.0
Royalty revenue								800,000	0		1,600,000	0
Contract research and development reimbursement commitment		80,000,000.0
Contract research and development expense								0	6,400,000		5,000,000.0	23,600,000
Contract research and development receivable								35,000,000.0			35,000,000.0		$ 100,000,000.0
Contract research and development current								20,000,000.0			20,000,000.0		70,000,000.0
Contract research and development long-term assets								15,000,000.0			15,000,000.0		30,000,000.0
Contra research and development reimbursement													50,000,000.0
Contra research and development reimbursement current													20,000,000.0
Contra research and development reimbursement long-term assets													30,000,000.0
Contra research and development reimbursement remaining													50,000,000.0
Collaboration and License Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member] \| License [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue								0	$ 0		0	$ 0
Collaboration and License Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member] \| ASC Topic 808
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 250,000,000.0
Development cost reimbursement		80,000,000.0
Collaboration and License Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone payments upon achievement of specified one time regulatory development and commercial milestone events		915,000,000.0
Collaboration and License Agreement [Member] \| Swedish Orphan Biovitrum AB (Publ) [Member] \| Maximum [Member] \| ASC Topic 808
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestone payments upon achievement of specified one-time regulatory and commercial milestone events		$ 915,000,000.0
University of Pennsylvania [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Annual maintenance fees											100,000
Milestone payments based on annual sales milestones													$ 5,000,000.0
Development milestone achievement					$ 1,000,000.0					$ 5,000,000.0
University of Pennsylvania [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestones payments								$ 3,200,000			3,200,000
Milestone payments based on annual sales milestones											5,000,000.0
2010 License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Annual maintenance fees											$ 100,000
Number of licensed products \| License								2			2
2010 License Agreement [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate milestones payments								$ 1,700,000			$ 1,700,000
Milestone payments based on annual sales milestones											$ 2,500,000
Sobi Agreement and Another Licensing Transaction [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense fee owed							$ 25,000,000.0
Research Collaboration Agreement [Member] \| Beam [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement term						5 years
Number of research programs \| Program						6
Up-front non-refundable payment															$ 50,000,000.0
Up-front payment on first anniversary of agreement on June 30, 2022						$ 25,000,000.0
Collaboration agreement maximum extendable term						2 years

Leases - Maturities of Operating Lease Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
2022	$ 1,669
2023	6,673
2024	5,913
2025	4,750
2026 and thereafter	4,839
Total future minimum lease payments less	23,844
Imputed interest	(3,134)
Total operating lease liabilities	$ 20,710	$ 21,196

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Level 1 [Member] \| Convertible Senior Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Convertible notes	$ 177.5	$ 290.7
Convertible notes, interest rate	3.50%	3.50%
Level 2 [Member] \| Development Liability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value	$ 320.0	$ 352.7

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2022

Fair Value, Nonrecurring [Member]

Schedule of Financial Instruments and the Related Fair Value Hierarchy of the Valuation Techniques Utilized

The following table presents the fair value of financial instruments recorded originally at amortized cost or fair value and not remeasured on a recurring basis (in thousands):


		September 30, 2022
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Cash and cash equivalents:	Money market funds	$	540,297	$	—	$	—	$	540,297
Total Financial Assets		$	540,297	$	—	$	—	$	540,297

		December 31, 2021
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Cash and cash equivalents	Money market funds	$	598,833	$	—	$	—	$	598,833
Total Financial Assets		$	598,833	$	—	$	—	$	598,833

Fair Value, Recurring [Member]

Schedule of Financial Instruments and the Related Fair Value Hierarchy of the Valuation Techniques Utilized

The following table presents the fair value of financial instruments recorded at fair value at inception and remeasured on a recurring basis (in thousands):


		September 30, 2022
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Marketable securities:	US government obligations	$	124,364		—		—	$	124,364
Total Financial Assets		$	124,364	$	—	$	—	$	124,364

		December 31, 2021
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Marketable securities:	US government obligations	$	60,358	$	—	$	—	$	60,358
Total Financial Assets		$	60,358	$	—	$	—	$	60,358

Leases - Schedule of Additional Information Related to Operating Lease Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
Operating Lease Assets	$ 19,522	$ 19,901
Operating Lease Liabilities	$ 20,710	$ 21,196
Weighted Average Remaining Term in years	3 years 9 months 14 days	4 years 7 months 28 days
Weighted Average discount rate used to measure outstanding lease liabilities	7.32%	7.71%

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, issued	110,476,000	97,524,000
Common stock, outstanding	110,476,000	97,524,000

Net Loss per Share

9 Months Ended

Sep. 30, 2022

Earnings Per Share [Abstract]

Net Loss per Share

15. Net Loss per Share

Since the Company was in a loss position for all periods presented, basic net loss per common share is the same as diluted net loss per common share for all periods presented as the inclusion of all potential common shares outstanding would have been anti-dilutive. Convertible notes and shares outstanding presented below were excluded from the calculation of diluted net loss per share, prior to the use of the treasury stock method, as their effect is anti-dilutive (in thousands):


	As of September 30,
	2022		2021
Convertible notes		2,379		4,884
Common stock options		12,511		12,954
Restricted stock units		3,568		1,071
Total		18,458		18,909

Long-term Debt - Additional Information (Detail)				1 Months Ended				3 Months Ended			9 Months Ended		12 Months Ended
Long-term Debt - Additional Information (Detail)	Jan. 01, 2021 USD ($)	May 12, 2020 USD ($)	Sep. 16, 2019 USD ($)	Jul. 31, 2022 USD ($) shares	Jul. 31, 2021 USD ($) shares	Jun. 30, 2021 USD ($) shares	Jan. 31, 2021 USD ($) shares	Sep. 30, 2022 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) shares	Mar. 31, 2021 USD ($) shares	Sep. 30, 2022 USD ($) d $ / shares	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	May 06, 2020 CounterParty $ / shares	Sep. 11, 2019 USD ($) CounterParty $ / shares
Debt Instrument [Line Items]
Aggregate principal amount converted											$ 98,086,000	$ 327,276,000
Loss on conversion of debt								$ 32,890,000	$ 61,102,000		32,890,000	100,589,000
Forfeiture of accrued interest in exchange of convertible notes											$ 1,287,000	4,171,000
ASU 2020-06 [Member]
Debt Instrument [Line Items]
Change in accounting principle accounting standards update adopted								true			true
Change in accounting principle accounting standards update adoption date								Jan. 01, 2021			Jan. 01, 2021
Increase (decrease) in net debt	$ 149,700,000
Decrease in net equity	149,700,000
Convertible notes	149,700,000
Non-cash interest expense	17,100,000
Amortization of debt issuance costs	1,100,000
Common Stock [Member]
Debt Instrument [Line Items]
Shares issued \| shares								3,073,000	6,071,000	3,976,000
2019 Convertible Notes [Member]
Debt Instrument [Line Items]
Long-term debt								$ 92,700,000			$ 92,700,000
Premium paid for capped call transactions													$ 28,400,000
2019 Convertible Notes [Member] \| ASU 2020-06 [Member]
Debt Instrument [Line Items]
Debt issuance costs	2,400,000
Convertible notes	74,900,000
2020 Convertible Notes [Member]
Debt Instrument [Line Items]
Premium paid for capped call transactions													43,100,000
2020 Convertible Notes [Member] \| ASU 2020-06 [Member]
Debt Instrument [Line Items]
Debt issuance costs	2,300,000
Convertible notes	$ 95,500,000
Capped Call Transactions [Member]
Debt Instrument [Line Items]
Number of counterparties \| CounterParty														2	2
Initial conversion price \| $ / shares														$ 39.4625	$ 39.4625
Initial cap price \| $ / shares															63.14
Sale price \| $ / shares															$ 31.57
Convertible Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt instrument, stated percentage			3.50%
Debt instrument, due and payment description											The Convertible Notes are senior unsecured obligations of the Company and bear interest at a rate of 3.5% per year payable semiannually in arrears on March 15 and September 15 of each year, beginning on March 15, 2020.
Debt instrument, frequency of periodic payment											semiannually
Maturity date			Sep. 15, 2026
Threshold trading days \| d											20
Threshold consecutive trading days \| d											30
Threshold percentage of stock price trigger											130.00%
Redemption period, start date											Sep. 20, 2023
Redemption price, percentage											100.00%
Amortization of debt issuance costs								100,000	$ 200,000		$ 400,000	800,000
Aggregate principal amount converted						$ 700,000
Aggregate principal amount converted into shares \| shares						18,775
Debt interest expense								1,200,000	2,300,000		4,800,000	10,200,000
Accrued semi annual coupon payable								1,100,000	2,100,000		4,400,000	9,400,000
Debt issuance costs gross								$ 1,200,000	$ 3,100,000		$ 1,200,000	$ 3,100,000	3,000,000.0
Long-term debt													$ 189,000,000.0
Convertible Senior Notes Due 2026 [Member] \| Prior to March 15, 2026 Convertible [Member]
Debt Instrument [Line Items]
Threshold trading days \| d											20
Threshold consecutive trading days \| d											30
Threshold percentage of stock price trigger											130.00%
Trading price per principal amount											$ 1,000
Convertible Senior Notes Due 2026 [Member] \| Prior to March 15, 2026 Convertible [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Threshold percentage of stock price trigger											98.00%
Convertible Senior Notes Due 2026 [Member] \| Common Stock [Member]
Debt Instrument [Line Items]
Terms of conversion											The Convertible Notes are convertible into shares of the Company’s common stock at an initial conversion rate of 25.3405 shares per $1,000 principal amount of Convertible Notes (equivalent to an initial conversion price of approximately $39.4625 per share of common stock).
Conversion ratio											0.0253405
Conversion price \| $ / shares								$ 39.4625			$ 39.4625
Convertible Senior Notes Due 2026 [Member] \| 2019 Convertible Notes [Member]
Debt Instrument [Line Items]
Net proceeds from the sale of the notes			$ 212,900,000
Payment of convertible debt discounts and commissions			6,600,000
Payment of convertible debt offering expenses			500,000
Payments of transactions cost			28,400,000
Debt instrument effective interest rate															10.50%
Debt instrument convertible carrying amount of liability component															$ 145,100,000
Debt discount															74,900,000
Debt issuance costs															7,100,000
Convertible Senior Notes Due 2026 [Member] \| 2019 Convertible Notes [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Conversion ratio					0.0253405		0.0253405
Debt issuance costs					$ 4,100,000		$ 3,300,000
Increase (decrease) in net debt					$ (197,000,000.0)		(122,800,000)
Aggregate principal amount converted							$ 126,100,000
Increase in shares outstanding \| shares					5,992,217		3,906,869
Shares issued \| shares					5,097,166		3,196,172
Additional shares issued \| shares					895,051		710,697
Additional shares issued for settlement of debt issuance cost paid \| shares					78,419		69,491		78,419
Loss on conversion of debt									$ 61,100,000	$ 39,500,000
Loss on conversion of debt related to additional shares issued									55,900,000	36,400,000
Additional amount issued in payment of issuance costs									5,200,000	$ 3,100,000
Forfeiture of accrued interest in exchange of convertible notes							$ 1,700,000
Convertible Senior Notes Due 2026 [Member] \| 2019 Convertible Notes [Member] \| Common Stock [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Aggregate principal amount converted into shares \| shares							3,906,869
Convertible Senior Notes Due 2026 [Member] \| 2019 Convertible Notes [Member] \| Liability Component [Member]
Debt Instrument [Line Items]
Debt issuance costs															4,700,000
Convertible Senior Notes Due 2026 [Member] \| 2019 Convertible Notes [Member] \| Equity Component [Member]
Debt Instrument [Line Items]
Debt issuance costs															$ 2,400,000
Convertible Senior Notes Due 2026 [Member] \| 2020 Convertible Notes [Member]
Debt Instrument [Line Items]
Net proceeds from the sale of the notes		$ 322,900,000
Payment of convertible debt discounts and commissions		5,700,000
Payment of convertible debt offering expenses		300,000
Payments of transactions cost		$ 43,100,000
Debt instrument effective interest rate		10.50%
Debt instrument convertible carrying amount of liability component		$ 204,500,000
Debt discount		95,500,000
Debt issuance costs		6,000,000.0
Convertible Senior Notes Due 2026 [Member] \| 2020 Convertible Notes [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Conversion ratio				0.0253405
Debt issuance costs				$ 1,300,000
Increase (decrease) in net debt				(96,800,000)
Aggregate principal amount converted				$ 98,100,000
Convertible notes held in treasury								$ 425,400,000			$ 425,400,000
Shares issued \| shares				2,485,548
Additional shares issued \| shares				541,470
Additional shares issued for settlement of debt issuance cost paid \| shares				46,132				46,132
Loss on conversion of debt								$ 32,900,000
Loss on conversion of debt related to additional shares issued								30,400,000
Additional amount issued in payment of issuance costs								2,500,000
Forfeiture of accrued interest in exchange of convertible notes								$ 1,300,000
Convertible Senior Notes Due 2026 [Member] \| 2020 Convertible Notes [Member] \| Common Stock [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Aggregate principal amount converted into shares \| shares				3,027,018	5,992,217
Convertible Senior Notes Due 2026 [Member] \| 2020 Convertible Notes [Member] \| Liability Component [Member]
Debt Instrument [Line Items]
Debt issuance costs		3,700,000
Convertible Senior Notes Due 2026 [Member] \| 2020 Convertible Notes [Member] \| Equity Component [Member]
Debt Instrument [Line Items]
Debt issuance costs		2,300,000
Convertible Senior Notes Due 2026 [Member] \| 2019 and 2020 Convertible Notes [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Aggregate principal amount converted					$ 201,100,000
Forfeiture of accrued interest in exchange of convertible notes									$ 2,500,000
Convertible Senior Notes Due 2026 [Member] \| Convertible Senior Notes [Member] \| Exchange Agreements [Member]
Debt Instrument [Line Items]
Increase in shares outstanding \| shares				3,027,018
Convertible Senior Notes Due 2026 [Member] \| Private Offering [Member] \| 2019 Convertible Notes [Member]
Debt Instrument [Line Items]
Principal amount			$ 220,000,000.0
Convertible Senior Notes Due 2026 [Member] \| Private Offering [Member] \| 2020 Convertible Notes [Member]
Debt Instrument [Line Items]
Principal amount		$ 300,000,000.0

Inventory - Schedule Of Inventory Current (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Raw materials	$ 25,955	$ 5,749
Semi-finished goods	33,124	10,058
Finished goods	674	479
Total Inventories	$ 59,753	$ 16,286

Other Comprehensive Income and Accumulated Other Comprehensive Income

9 Months Ended

Sep. 30, 2022

Equity [Abstract]

Other Comprehensive Income and Accumulated Other Comprehensive Income

10. Other Comprehensive Income and Accumulated Other Comprehensive Income

The following tables summarize the changes in accumulated other comprehensive income/(loss), by component for the nine months ended September 30, 2022 and September 30, 2021 (in thousands):


	Unrealized Gains (Losses) from Marketable Securities			Foreign Currency Translation Adjustment			Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2021	$	1		$	(2,091	)	$	(2,090	)
Net other comprehensive income (loss)		(52	)		83			31
Balances, March 31, 2022		(51	)		(2,008	)		(2,059	)
Net other comprehensive loss		(766	)		(369	)		(1,135	)
Balances, June 30, 2022		(817	)		(2,377	)		(3,194	)
Net other comprehensive income (loss)		435			(268	)		167
Balances, September 30, 2022	$	(382	)	$	(2,645	)	$	(3,027	)


	Unrealized Gains (Losses) from Marketable Securities			Foreign Currency Translation Adjustment			Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2020	$	(8	)	$	(109	)	$	(117	)
Net other comprehensive income (loss)		79			(1,582	)		(1,503	)
Balances, March 31, 2021		71			(1,691	)		(1,620	)
Net other comprehensive loss		(35	)		(174	)		(209	)
Balances, June 30, 2021		36			(1,865	)		(1,829	)
Net other comprehensive income (loss)		(25	)		(156	)		(181	)
Balances, September 30, 2021	$	11		$	(2,021	)	$	(2,010	)

Nature of Organization and Operations

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of Organization and Operations

1. Nature of Organization and Operations

Apellis Pharmaceuticals, Inc. (the “Company”) is a commercial-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutic compounds to treat diseases with high unmet needs through the inhibition of the complement system, which is an integral component of the immune system, at the level of C3, the central protein in the complement cascade.

The Company was incorporated in September 2009 under the laws of the State of Delaware. The Company’s principal executive offices are located in Waltham, Massachusetts.

The Company’s operations since inception have been limited to organizing and staffing the Company, acquiring rights to product candidates, business planning, raising capital, developing its product candidates, and commercializing EMPAVELI (pegcetacoplan) for the treatment of paroxysmal nocturnal hemoglobinuria (“PNH”).

The Company is subject to risks common in the biotechnology industry including, but not limited to, raising additional capital, development by its competitors of new technological innovations, its ability to successfully complete preclinical and clinical development of product candidates and receive timely regulatory approval of products, market acceptance of the Company’s products, protection of proprietary technology, healthcare cost containment initiatives, and compliance with governmental regulations, including those of the U.S. Food and Drug Administration (“FDA”).

Liquidity and Going Concern

The accompanying unaudited condensed consolidated financial statements have been prepared on the basis of the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. As of November 7, 2022, the date of issuance of these unaudited condensed consolidated financial statements, the Company believes that its cash and cash equivalents and marketable securities of $708.6 million as of September 30, 2022 will be sufficient to fund its operations and capital expenditures for at least the next twelve months. The Company’s future viability beyond that point is dependent on its ability to raise additional capital to finance its operations.

There are uncertainties associated with the Company’s ability to (1) obtain additional debt or equity financing on terms that are favorable to the Company, (2) enter into collaborative agreements with strategic partners, and (3) succeed in its future operations. If the Company is not able to obtain the required funding for its operations or is not able to obtain funding on terms that are favorable to the Company, it could be forced to delay, reduce or eliminate its research and development programs or future commercialization efforts and its business could be materially harmed.

Marketable Securities

9 Months Ended

Sep. 30, 2022

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

9. Marketable Securities

The amortized cost, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security as of September 30, 2022 and December 31, 2021 were as follows (in thousands):


	As of September 30, 2022
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Government-related obligations	$	124,746	$	—	$	(382	)	$	124,364

	As of December 31, 2021
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Government-related obligations	$	60,357	$	3	$	(2	)	$	60,358

All available-for-sale securities mature in one year or less.

Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2022

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost, Gross Unrealized Holding Losses and Fair Value of Available-for-Sale Debt Securities by Type of Security


	As of September 30, 2022
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Government-related obligations	$	124,746	$	—	$	(382	)	$	124,364

	As of December 31, 2021
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. Government-related obligations	$	60,357	$	3	$	(2	)	$	60,358

Nature of Organization and Operations - Additional Information (Detail) $ in Millions	Sep. 30, 2022 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents and marketable securities	$ 708.6

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense	$ 446	$ 0	$ 2,140	$ 0
U.S. federal statutory rate			21.00%
Minimum percentage of tax position likelihood of being realized upon examination by taxing authorities			50.00%
Unrecognized income tax benefits	$ 1,900		$ 1,900

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Net Loss per Share - Summary of Shares Outstanding that were Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	18,458	18,909
Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	2,379	4,884
Common Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	12,511	12,954
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3,568	1,071

Development Liability and Development Derivative Liability - Additional Information (Detail) $ in Thousands			1 Months Ended			3 Months Ended				9 Months Ended
	Jan. 29, 2020 USD ($)	Feb. 28, 2019 USD ($) Installment	May 31, 2022 USD ($)	Jan. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 07, 2019 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Interest expense						$ 7,903	$ 2,282			$ 24,888	$ 10,223
Loss from remeasurement of development derivative liability							$ 4,219	$ 21,180	$ 17,084		$ 42,483
Level 3 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Implied cost of borrowing discount rates											11.90%
SFJ Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from SFJ agreement	$ 140,000	$ 60,000
Additional funding amount upon achievement of development milestones		$ 60,000
Number of milestone payments \| Installment		3
Increase in additional funding for development costs												$ 20,000
Payment made under agreement				$ 5,000	$ 4,000
First annual payment under agreement			$ 11,500
Interest expense						$ 6,700				$ 20,100
SFJ Agreement [Member] \| Level 3 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Implied cost of borrowing discount rates											8.00%
SFJ Agreement [Member] \| Regulatory Approval Granted US Food and Drug Administration [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Obligated to pay initial payment		$ 4,000
Aggregate amount of additional annual payments		$ 226,000
Number of additional annual payments \| Installment		6
SFJ Agreement [Member] \| Regulatory Approval Granted by EMA [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Obligated to pay initial payment		$ 5,000
Aggregate amount of additional annual payments		$ 225,000
Number of additional annual payments \| Installment		6

Other Comprehensive Income and Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income/(Loss), by Component (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 334,418	$ 462,235	$ 198,662	$ (141,493)	$ 51,658	$ 204,557
Ending balance	307,416	334,418	462,235	(57,325)	(141,493)	51,658
Unrealized Gains (Losses) from Marketable Securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(817)	(51)	1	36	71	(8)
Net other comprehensive income (loss)	435	(766)	(52)	(25)	(35)	79
Ending balance	(382)	(817)	(51)	11	36	71
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(2,377)	(2,008)	(2,091)	(1,865)	(1,691)	(109)
Net other comprehensive income (loss)	(268)	(369)	83	(156)	(174)	(1,582)
Ending balance	(2,645)	(2,377)	(2,008)	(2,021)	(1,865)	(1,691)
Total Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(3,194)	(2,059)	(2,090)	(1,829)	(1,620)	(117)
Net other comprehensive income (loss)	167	(1,135)	31	(181)	(209)	(1,503)
Ending balance	$ (3,027)	$ (3,194)	$ (2,059)	$ (2,010)	$ (1,829)	$ (1,620)

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

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+ Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Topic 235
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+ Details

Leases - Supplemental Cash Flow Information Related to Operating Leases (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Leases [Abstract]
Operating cash flows for operating leases	$ 5,499	$ 4,476
Operating lease assets obtained in exchange for lease obligations		$ 5,675

Development Liability and Development Derivative Liability (Tables)

9 Months Ended

Sep. 30, 2022

Research and Development [Abstract]

Summary of Development Liability

The following table summarizes the development liability (in thousands):


	September 30, 2022			December 31, 2021			Effective Interest Rate
Development liability	$	439,500		$	456,000			7.91	%
Less: Unamortized discount to development liability		(83,212	)		(103,265	)
Less: Current portion of development liability, net of discount		(16,146	)		(7,584	)
Total long term development liability	$	340,142		$	345,151

Schedule of Development Derivative Liability

The following table presents a rollforward of the development derivative liability for the nine months ended September 30, 2021 (in thousands):


Balance at fair market value, January 1, 2021	$	257,868
Loss from remeasurement of development derivative liability		17,084
Balance at fair market value, March 31, 2021	$	274,952
Amount repaid under the SFJ agreement and SFJ amendment		(4,000	)
Loss from remeasurement of development derivative liability		21,180
Balance at fair market value, June 30, 2021	$	292,132
Amount repaid under the SFJ agreement and SFJ amendment		—
Loss from remeasurement of development derivative liability		4,219
Balance at fair market value, September 30, 2021	$	296,351

Net Loss per Share (Tables)

9 Months Ended

Sep. 30, 2022

Earnings Per Share [Abstract]

Summary of Shares Outstanding that were Excluded from Calculation of Diluted Net Loss Per Share

Convertible notes and shares outstanding presented below were excluded from the calculation of diluted net loss per share, prior to the use of the treasury stock method, as their effect is anti-dilutive (in thousands):


	As of September 30,
	2022		2021
Convertible notes		2,379		4,884
Common stock options		12,511		12,954
Restricted stock units		3,568		1,071
Total		18,458		18,909

Commitments and Contingencies

9 Months Ended

Sep. 30, 2022

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

14. Commitments and Contingencies

The Company has certain non-cancelable purchase obligations related to the manufacturing of drug substance and drug product with Bachem Americas, Inc. and Bachem AG, under which the Company has agreed to purchase a significant portion of its requirements for the pegcetacoplan drug substance over the next five years, and a commercial supply agreement with NOF Corporation, under which the Company has agreed to purchase activated polyethylene glycol derivative, or PEG, which is a component of pegcetacoplan. Under these agreements, as of September 30, 2022, the Company is obligated to pay up to $112.1 million to these vendors. In addition, the Company has other non-cancelable purchase agreements as of September 30, 2022, under which it is obligated to pay up to $6.2 million to these vendors.

Following regulatory approval by the FDA and EMA for the use of pegcetacoplan as a treatment for PNH, the Company has certain payment and other obligations under the SFJ agreement, which are discussed above in Note 6 Development Liability and Development Derivative Liability.

The Company is a party to a master lease agreement under which the Company leases vehicles with initial terms of 36 months from the date of delivery. If the Company were unable to take delivery of a previously ordered vehicle, the Company may incur nominal fees.

Indemnifications—In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend indemnified parties for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has not incurred any cost to defend lawsuits or settle claims related to these indemnification provisions.

Legal—During the normal course of business, the Company may be a party to legal claims that may not be covered by insurance. Management does not believe that any such claims would have a material impact on the Company’s consolidated financial statements.

Development Liability and Development Derivative Liability

9 Months Ended

Sep. 30, 2022

Research and Development [Abstract]

Development Liability and Development Derivative Liability

6. Development Liability and Development Derivative Liability

On February 28, 2019, the Company entered into a development funding agreement (the “SFJ agreement”), with SFJ Pharmaceuticals Group (“SFJ”), under which SFJ agreed to provide funding to the Company to support the development of pegcetacoplan for the treatment of patients with PNH. Pursuant to the SFJ agreement, SFJ paid the Company $60.0 million following the signing of the agreement and agreed to pay the Company up to an additional $60.0 million in the aggregate in three equal installments upon the achievement of specified development milestones with respect to the Company’s Phase 3 program for pegcetacoplan in PNH.

On June 7, 2019, the Company and SFJ amended the development funding agreement, (the “SFJ amendment”). Under the SFJ amendment, SFJ agreed to make an additional $20.0 million funding payment to the Company to support the development of systemic pegcetacoplan for the treatment of patients with PNH.

As of January 29, 2020, the Company had received a total of $140.0 million from SFJ as the Company met milestones as identified in the SFJ agreement. The Company did not receive any additional funds from SFJ after January 29, 2020.

Under the SFJ agreement, following regulatory approval by the FDA for the use of systemic pegcetacoplan as a treatment for PNH, the Company is obligated to pay SFJ an initial payment of $4.0 million and then an additional $226.0 million in the aggregate in six additional annual payments with the majority of the payments being made from the third anniversary to the sixth anniversary of regulatory approval. The Company obtained regulatory approval by the FDA on May 14, 2021 and paid to SFJ the initial payment of $4.0 million in June 2021 and the first annual payment of $11.5 million in May 2022. The subsequent annual payments remaining are due and payable in May of each year from 2023 through 2027.

Under the SFJ agreement, following regulatory approval by the European Medicines Agency (the “EMA”) for the use of systemic pegcetacoplan as a treatment for PNH, the Company is obligated to pay SFJ an initial payment of $5.0 million and then an additional $225.0 million in the aggregate in six additional annual payments with the majority of the payments being made from the third anniversary to the sixth anniversary of regulatory approval. The Company obtained regulatory approval by the EMA on December 15, 2021 and paid to SFJ the initial payment of $5.0 million in January 2022. The subsequent annual payments are due and payable in December of each year from 2022 through 2027.

Additionally, the Company granted a security interest to SFJ in all of its assets, excluding intellectual property and license agreements to which it is a party. In connection with the grant of the security interest, the Company agreed to certain affirmative and negative covenants, including restrictions on its ability to pay dividends, incur additional debt or enter into licensing transactions with respect to its intellectual property, other than specified types of licenses.

Prior to EMA approval on December 15, 2021, the SFJ agreement was presented as a derivative liability on the consolidated balance sheet and, as such, was recorded at fair value and remeasured each quarter. As the variability of the future payments derived from the underlying contingency (i.e., EMA approval and FDA approval) no longer exists, the Company remeasured the development derivative liability on December 15, 2021 and reclassified it from a development derivative liability to a development liability, with subsequent accounting to follow an effective interest accretion schedule to the fixed payment amounts.

From December 15, 2021 to the final annual payment due in December 2027, the development liability will be accreted from its initial carrying amount to the total payment amount using the effective interest rate method under FASB ASC Topic 835, Interest, over the remaining life of the SFJ agreement. The difference between the carrying amount and the total payment amount is presented as a discount to the development liability. The accretion is recorded as interest expense in the unaudited condensed consolidated statement of operations.

The following table summarizes the development liability (in thousands):


	September 30, 2022			December 31, 2021			Effective Interest Rate
Development liability	$	439,500		$	456,000			7.91	%
Less: Unamortized discount to development liability		(83,212	)		(103,265	)
Less: Current portion of development liability, net of discount		(16,146	)		(7,584	)
Total long term development liability	$	340,142		$	345,151

For the three and nine months ended September 30, 2022, interest expense of $6.7 million and $20.1 million, respectively, was recorded for the accretion of the development liability.

The following table presents a rollforward of the development derivative liability for the nine months ended September 30, 2021 (in thousands):


Balance at fair market value, January 1, 2021	$	257,868
Loss from remeasurement of development derivative liability		17,084
Balance at fair market value, March 31, 2021	$	274,952
Amount repaid under the SFJ agreement and SFJ amendment		(4,000	)
Loss from remeasurement of development derivative liability		21,180
Balance at fair market value, June 30, 2021	$	292,132
Amount repaid under the SFJ agreement and SFJ amendment		—
Loss from remeasurement of development derivative liability		4,219
Balance at fair market value, September 30, 2021	$	296,351

For the nine months ended September 30, 2021, the total change in fair value of $42.5 million was recorded in loss from remeasurement of development derivative liability in the unaudited condensed consolidated statement of operations.

The derivative fair value as of September 30, 2021 was a Level 3 fair value measurement and was valued using a scenario-based discounted cash flow method, whereby each scenario made assumptions about the probability and timing of cash flows, and such cash flows are present valued using a risk-adjusted discount rate. The analysis is calibrated such that the value of the derivative as of the date of the SFJ agreement was consistent with an arm’s-length transaction. Key inputs to the Level 3 fair value model included (i) the probability and timing of achieving stated development milestones to receive the next tranches of funding, (ii) the probability and timing of achieving FDA and EMA approval, (iii) SFJ’s cost of borrowing (8.0%), and (iv) the Company’s cost of borrowing (11.9%).

SFJ’s implied cost of borrowing was 8.0% and the Company’s implied cost of borrowing was 11.9% as of September 30, 2021. These implied costs of borrowing were determined assuming the SFJ agreement was initially executed with arm’s-length terms. If the SFJ agreement was instead not determined to be an arm’s-length transaction, then implied discount rates could differ.

Prepaid Assets and Accrued Expenses - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Prepaid Assets And Accrued Expenses [Abstract]
Prepaid research and development	$ 16.0	$ 12.0

Prepaid Assets and Accrued Expenses (Tables)

9 Months Ended

Sep. 30, 2022

Prepaid Assets And Accrued Expenses [Abstract]

Schedule of Accrued Expenses

Accrued expenses are as follows (in thousands):


	September 30,		December 31,
	2022		2021
Accrued research and development	$	28,071	$	35,217
Accrued cost of research collaboration		—		25,000
Accrued license fee		—		5,000
Accrued royalties		723		—
Accrued payroll liabilities		33,467		25,212
Other		17,517		12,810
Total	$	79,778	$	103,239

Leases (Tables)

9 Months Ended

Sep. 30, 2022

Leases [Abstract]

Schedule of Additional Information Related to Operating Lease Assets and Liabilities

Additional information related to the operating lease assets and liabilities is as follows (in thousands):


	September 30,			December 31,
	2022			2021
Operating Lease Assets	$	19,522		$	19,901
Operating Lease Liabilities	$	20,710		$	21,196
Weighted Average Remaining Term in years		3.79		4.66
Weighted Average discount rate used to measure outstanding lease liabilities		7.32	%		7.71	%

Supplemental Cash Flow Information Related to Operating Leases

Supplemental cash flow information related to operating leases for the nine months ended September 30 is as follows (in thousands):


	2022		2021
Operating cash flows for operating leases	$	5,499	$	4,476
Operating lease assets obtained in exchange for lease obligations	$	—	$	5,675

Maturities of Operating Lease Liabilities

The maturities of the Company’s operating lease liabilities as of September 30, 2022 are as follows (in thousands):


2022		1,669
2023		6,673
2024		5,913
2025		4,750
2026 and thereafter		4,839
Total future minimum lease payments less		23,844
Imputed interest		(3,134	)
Total operating lease liabilities	$	20,710

Inventory (Tables)

9 Months Ended

Sep. 30, 2022

Inventory Disclosure [Abstract]

Schedule Of Inventory Current

The Company’s inventory of EMPAVELI consisted of the following as of September 30, 2022, and December 31, 2021 (in thousands):


	September 30,		December 31,
	2022		2021
Raw materials	$	25,955	$	5,749
Semi-finished goods		33,124		10,058
Finished goods		674		479
Total Inventories	$	59,753	$	16,286

License and Collaboration Agreements

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

License and Collaboration Agreements

13. License and Collaboration Agreements

Sobi License and Collaboration Agreement

On October 27, 2020, the Company and its subsidiaries, Apellis Switzerland GmbH and APL DEL Holdings, LLC entered into a Collaboration and License Agreement (the “Sobi collaboration agreement”) with Swedish Orphan Biovitrum AB (Publ) (“Sobi”), concerning the development and commercialization of pegcetacoplan and specified other structurally and functionally similar compstatin analogues or derivatives for use systemically or for local non-ophthalmological administration (collectively referred to as the “Licensed Products”).

Under the Sobi collaboration agreement, the Company granted Sobi an exclusive (subject to certain retained rights of the Company), sublicensable license of certain patent rights and know-how to develop and commercialize Licensed Products in all countries outside of the United States. The Company retains the right to commercialize Licensed Products in the United States, and, subject to specified limitations, to develop Licensed Products worldwide for commercialization in the United States.

Under the Sobi collaboration agreement, the Company and Sobi have agreed to collaborate to develop Licensed Products for the treatment of PNH, cold agglutinin disease, hematopoietic stem cell transplantation-associated thrombotic microangiopathy, C3 glomerulopathy and immune complex membranoproliferative glomerulonephritis, and amyotrophic lateral sclerosis (collectively the “Initial Indications”), and any other indications subsequently agreed upon by the parties, for commercialization by or on behalf of the Company in the United States and by or on behalf of Sobi outside of the United States. If the parties do not agree to jointly pursue any development activities for the Licensed Products (whether for an Initial Indication or otherwise), the party proposing to pursue such activities may conduct such activities at its sole expense (with the non-proposing party having the right to obtain rights to the data generated by such development activities by paying a specified percentage of that expense), subject to agreed-upon exceptions that limit each party’s unilateral development rights.

The initial development plan sets forth the initial development activities to be conducted by each of the Company and Sobi, with the Company bearing all costs incurred in conducting the activities set forth in such initial development plan, as well as certain specified additional costs that are not included in the initial development plan that may be incurred by the parties in developing Licensed Products for PNH in the European Union and the United Kingdom. The Company and Sobi have formed several governance committees to oversee the development and manufacture, and to review and discuss the commercialization, of Licensed Products.

The Company shall supply Licensed Products to Sobi for development and for commercialization outside of the United States in accordance with a supply agreement to be negotiated by the parties. The collaboration agreement grants Sobi the right to perform or have performed drug product manufacturing of Licensed Products for development and for commercialization outside the United States and to manufacture or have manufactured drug substance under certain circumstances.

Sobi paid the Company an upfront payment of $250.0 million in November 2020 and has agreed to pay up to an aggregate of $915.0 million upon the achievement of specified one-time regulatory development and commercial milestone events, of which the Company received $50.0 million in April 2022 for the achievement of a regulatory development milestone in Europe. Sobi also agreed to reimburse the Company for up to $80.0 million in development costs, of which the Company received $25.0 million in January 2021 and $20.0 million in January 2022. The Company will also be entitled to receive tiered, double-digit royalties (ranging from high teens to high twenties) on sales of Licensed Products outside of the United States, subject to customary deductions and third-party payment obligations, until the latest to occur of: (i) expiration of the last-to-expire of specified licensed patent rights; (ii) expiration of regulatory exclusivity; and (iii) ten (10) years after the first commercial sale of the applicable Licensed Product, in each case on a Licensed Product-by-Licensed Product and country-by-country basis. Under the Sobi collaboration agreement, the Company remains responsible for its license fee obligations (including royalty obligations) to the University of Pennsylvania as a licensor of the Company and for its payment obligations to SFJ.

Sobi Accounting Analysis

The Company has determined that the Sobi collaboration agreement is within the scope of FASB ASC Topic 808, Collaborative Arrangement Guidance and Considerations, (“ASC 808”) as a contractual arrangement that involves a joint operating activity whereby both parties are (i) active participants in the activity and (ii) exposed to certain significant risks and rewards dependent on the commercial success of the activity. ASC 808 does not address measurement or recognition matters but allows for analogizing to FASB ASC Topic 606, Revenue from Contracts with Customers, (“ASC 606”). Pursuant to ASC 606, the Company performed the following five steps: (i) identified the contract(s) with a customer; (ii) identified the performance obligations in the contract; (iii) determined the transaction price; (iv) allocated the transaction price to the performance obligations in the contract; and (v) recognized revenue when (or as) the entity satisfies a performance obligation.

The Company identified the following material distinct promises under the Sobi collaboration agreement: (1) licenses to develop and commercialize pegcetacoplan (“Licenses to IP”), and (2) performance of research and development services. The Company determined the promises to be distinct because Sobi can benefit from each of the license and the development services on their own or with readily available services. The Company could have provided the license without any development services and Sobi would have been able to benefit from it by obtaining development services from another provider as the Licensed Products are at a more mature stage in their life cycle.

Under the Sobi collaboration agreement, Sobi agreed to pay the Company


	i)	a fixed amount of $250.0 million in an upfront payment in November 2020;


	ii)	a fixed amount of an additional $80.0 million in development reimbursements, payable yearly in four tranches in amounts determined based upon actual expenses incurred by the Company;


	iii)	up to an aggregate of $915.0 million upon the achievement of specified one-time regulatory and commercial milestone events; and


	iv)	tiered, double-digit royalties, ranging from high teens to high twenties, on sales of Licensed Products outside of the United States, subject to customary deductions and third-party payment obligations.

At contract inception, the $250.0 million non-refundable payment and the $80.0 million reimbursements were fixed proceeds. The Company evaluated whether Sobi is a customer for either of the distinct promises in the Sobi collaboration agreement. Under the Licenses to IP, the Company determined that Sobi is a customer as the know-how provided and the right granted by the Company to Sobi are outputs of the Company’s business activities for which the Company will receive consideration. With respect to research and development activity, management determined that there is no vendor relationship as performing research and development activities for others is not a part of the Company’s ongoing central operations. Based upon the evaluation of the relative fair values, the Company allocated the purchase price of $250.0 million and the related milestones and royalties to the License to IP and $80.0 million to performance of research and development activities.

The milestone and royalty payments are subject to activities outside the control of the Company. Per ASC 606, the Company considers this to be a customer/ vendor relationship, therefore, the Company will include the regulatory milestone payments in the

total transaction price when it is probable that a significant reversal of revenue would not occur in a future period. The Company will recognize commercial milestone and royalty revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which the commercial milestone or royalty has been allocated has been satisfied. In case of commercial milestone or royalty payments, the Company will recognize revenue in the same period that the sales are completed for which the Company is contractually entitled to the milestone or percentage-based royalty payment. To date, the Company has not recognized any commercial milestone revenue resulting from any of its licensing arrangements. The Company has recognized $0.8 million and $1.6 million of royalty revenue for the three and nine months ended September 30, 2022, respectively. Management periodically assesses the elements of the contract and re-evaluates revenue recognition as necessary.

Pursuant to ASC 606, during the year ended December 31, 2020, the Company recognized the $250.0 million in revenue as this is the amount allocated to the license. The $80.0 million reimbursement for research and development activities does not constitute a customer/vendor relationship and thus is not in the scope of ASC 606. As ASC 808 does not include recognition guidance, the Company has established an accounting policy to recognize the payments under the reimbursement as a receivable on the consolidated balance sheet in an amount that is to be reimbursed based upon expense incurred by the Company, with a contra-research and development expense recognized in the consolidated statement of operations, over time as the expenses are incurred.

Under the Sobi collaboration agreement, for the three and nine months ended September 30, 2022 and 2021, the Company did not recognize licensing revenue. For the three and nine months ended September 30, 2022, the Company recognized $0.8 million and $1.6 million, respectively, of royalty revenue. The Company did not recognize any royalty revenue for the three and nine months ended September 30, 2021. For the nine months ended September 30, 2022, the Company recognized $5.0 million for contra-research and development expense in the unaudited condensed consolidated statement of operations related to the $80.0 million reimbursement commitment from Sobi. The Company did not recognize any contra-research and development expense for the three months ended September 30, 2022. For the three and nine months ended September 30, 2021, the Company recognized $6.4 million and $23.6 million, respectively, for contra-research and development expense. Since contract inception, the Company has recognized $80.0 million in contra-research and development expenses.

As of September 30, 2022, the Company recorded a receivable of $35.0 million, with $20.0 million in current assets and $15.0 million in long-term assets, on the unaudited condensed consolidated balance sheet. The total receivable balance as of September 30, 2022 is for contra-research and development expenses incurred but not yet reimbursed from Sobi.

As of December 31, 2021, the Company recorded a receivable of $100.0 million, with $70.0 million in current assets and $30.0 million in long-term assets. Of the $100.0 million receivable as of December 31, 2021, $50.0 million is for contra-research and development reimbursement from Sobi, with $20.0 million and $30.0 million in current and long-term assets, respectively. The remaining $50.0 million receivable as of December 31, 2021 in current assets is for the achievement of the development milestone for first regulatory and reimbursement approval in Europe.

University of Pennsylvania License Agreement

The Company is a party to a license agreement with the Trustees of the University of Pennsylvania (“Penn”) for an exclusive, worldwide license to specified patent rights. The Company is required to pay annual maintenance fees of $0.1 million until the first sale of a licensed product. The Company is also required to make milestone payments aggregating up to $3.2 million based upon the achievement of specified development and regulatory milestones and up to $5.0 million based upon the achievement of specified annual sales milestones with respect to each licensed product, and to pay low single-digit royalties based on net sales of each licensed product and with minimum quarterly royalty thresholds. In addition, the Company is obligated to pay a specified portion of income it receives from sublicensees.

In addition, the Company is also party to a license agreement with Penn for an exclusive, worldwide license to specified patent rights for the development and commercialization of products in fields of use, as defined therein. The Company is required to pay annual maintenance fees of $0.1 million until the first sale of a licensed product. The Company is required to make milestone payments aggregating up to $1.7 million, based upon the achievement of development and regulatory approval milestones, and up to $2.5 million, based upon the achievement of annual sales milestones with respect to each of the first two licensed products. The license agreement also requires the Company to pay low single digit royalties based on net sales of each licensed product, subject to minimum quarterly royalty thresholds. In addition, the Company is obligated to pay a specified portion of income it receives from sublicensees. In January 2021, the Company paid $25.0 million for a sublicense fee owed to Penn related to the Sobi collaboration agreement and another licensing transaction. In August 2021 the Company paid $1.0 million to Penn upon the achievement of a development milestone. In June 2022 the Company paid an additional $5.0 million to Penn upon the achievement of a development milestone, which was accrued as of December 31, 2021, as it was considered probable at that time. The $5.0 million development milestone was recorded in accrued expenses on the unaudited condensed consolidated balance sheet as of December 31, 2021.

Beam Research Collaboration

In June 2021, the Company entered into an exclusive five-year research collaboration (the “Beam collaboration agreement”) with Beam Therapeutics, Inc. (“Beam”) focused on the use of Beam’s proprietary base editing technology to discover new treatments for complement-driven diseases. The Company and Beam agreed to collaborate on up to six research programs focused on C3 and other complement targets in the eye, liver and brain. Under the terms of the Beam collaboration agreement, Apellis is responsible for selecting specific genes within the complement system in various organs including the eye, liver and brain (the “Target List”) and providing analytical support while Beam will apply its base editing technology and conduct preclinical research on up to six base editing programs for the Target List. During the first five years of the Beam collaboration agreement, Beam is prohibited from developing on its own or with a third party any base editing therapies associated with the items on the Target List but does not prevent Beam from licensing its intellectual property to a third-party for another purpose outside of the Target List. The Company will have exclusive rights to license each of the six programs and will assume responsibility for subsequent development and commercialization. Beam may elect to enter a 50-50 co-development and U.S. co-commercialization agreement with the Company with respect to any one program licensed under the Beam collaboration agreement and upon such election any license agreement in place at that time, would be terminated.

As part of the Beam collaboration agreement, the Company agreed to pay a $50.0 million up-front, non-refundable payment to Beam, which the Company paid in July 2021. In June 2022, the Company paid $25.0 million which was recorded as a cost of research collaboration expense for the year ended December 31, 2021, as it was considered probable of achievement. The Company and Beam are each responsible for their own costs during the research collaboration. If and after the opt-in license rights are exercised for each of the up to six programs, Beam will be eligible to receive development, regulatory and sales milestones from the Company, as well as royalty payments on sales. The Beam collaboration agreement has an initial term of five years and may be extended up to two years on a per year program-by-program basis.

The Company analyzed the Beam research collaboration agreement pursuant to ASC 808 to assess whether the agreement involved joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. Since each party is actively participating in this activity and exposed to significant risks and rewards related to the activity through each party’s costs will be accounted for under ASC 808.

Since ASC 808 does not provide recognition guidance, the Company referred to the guidance under FASB ASC Topic 730, Research and Development (“ASC 730”), to arrangements involving payments by the Company. ASC 730 requires the Company to recognize research and developments costs as expense as incurred since the payment was made for the use of Beam’s intellectual property and research and development services and there is no alternative use.

Commitments and Contingencies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2022 USD ($)
Commitments And Contingencies [Line Items]
Incurred any cost to defend lawsuits or settle claims	$ 0
Vehicles [Member]
Commitments And Contingencies [Line Items]
Operating lease, term of contract	36 months
Bachem and NOF
Commitments And Contingencies [Line Items]
Non-cancellable purchase obligation substance over period	5 years
Non-cancellable purchase commitments	$ 112,100,000
Other Commitment	$ 6,200,000

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Current assets:
Cash and cash equivalents	$ 584,189	$ 640,192
Marketable securities	124,364	60,358
Accounts receivable	8,091	10,103
Inventory	59,753	16,286
Prepaid assets	30,356	24,868
Restricted cash	1,259	1,563
Other current assets	23,925	70,677
Total current assets	831,937	824,047
Non-current assets:
Right-of-use assets	19,522	19,901
Property and equipment, net	5,681	6,177
Other assets	15,752	31,640
Total assets	872,892	881,765
Current liabilities:
Accounts payable	14,099	16,909
Accrued expenses	79,778	103,239
Current portion of development liability	16,146	7,584
Current portion of right-of-use liabilities	5,423	4,115
Total current liabilities	115,446	131,847
Long-term liabilities:
Long-term development liability	340,142	345,151
Convertible senior notes	92,663	189,024
Right-of-use liabilities	15,287	17,081
Other liabilities	1,938
Total liabilities	565,476	683,103
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized, and zero shares issued and outstanding at September 30, 2022 and December 31, 2021	0	0
Common stock, $0.0001 par value; 200,000 shares authorized at September 30, 2022 and December 31, 2021; 110,476 shares issued and outstanding at September 30, 2022, and 97,524 shares issued and outstanding at December 31, 2021	11	10
Additional paid-in capital	2,453,301	1,857,430
Accumulated other comprehensive loss	(3,027)	(2,090)
Accumulated deficit	(2,142,869)	(1,656,688)
Total stockholders' equity	307,416	198,662	$ (141,493)
Total liabilities and stockholders' equity	$ 872,892	$ 881,765

Leases

9 Months Ended

Sep. 30, 2022

Leases [Abstract]

Leases

8. Leases

The underlying assets of the Company’s leases primarily relate to office space leases, but also include some equipment leases. The Company determines if an arrangement qualifies as a lease at its inception.

As a practical expedient permitted under FASB ASC Topic 842, Leases, the Company elected to account for the lease and non-lease components as a single lease component for all leases of which it is the lessee. Lease payments, which may include lease and non-lease components, are included in the measurement of the Company’s lease liabilities to the extent that such payments are either fixed amounts or variable amounts that depend on a rate or index as stipulated in the lease contract. When the Company cannot readily determine the rate implicit in the lease, the Company determines its incremental borrowing rate by using the rate of interest that it

would have to pay to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment.

The Company enters into lease agreements with terms generally ranging from 2-7 years. Some of the Company’s lease agreements include Company options to extend the lease on a month-to-month basis or for set periods for up to five years. Many of these leases also include options to terminate the leases within one year or per other contractual terms. Renewal and termination options were generally not included in the lease term for the Company’s existing operating leases.

As of September 30, 2022 and December 31, 2021, all leases were classified as operating lease assets and liabilities. Additional information related to the operating lease assets and liabilities is as follows (in thousands):


	September 30,			December 31,
	2022			2021
Operating Lease Assets	$	19,522		$	19,901
Operating Lease Liabilities	$	20,710		$	21,196
Weighted Average Remaining Term in years		3.79		4.66
Weighted Average discount rate used to measure outstanding lease liabilities		7.32	%		7.71	%

For the three months ended September 30, 2022 and 2021, the total lease cost for operating lease expense was $1.7 million and $1.4 million, respectively. For the nine months ended September 30, 2022 and 2021, the total lease cost for operating lease expense was $4.6 million and $4.2 million, respectively.

Supplemental cash flow information related to operating leases for the nine months ended September 30 is as follows (in thousands):


	2022		2021
Operating cash flows for operating leases	$	5,499	$	4,476
Operating lease assets obtained in exchange for lease obligations	$	—	$	5,675

The maturities of the Company’s operating lease liabilities as of September 30, 2022 are as follows (in thousands):


2022		1,669
2023		6,673
2024		5,913
2025		4,750
2026 and thereafter		4,839
Total future minimum lease payments less		23,844
Imputed interest		(3,134	)
Total operating lease liabilities	$	20,710

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted and, accordingly, the consolidated balance sheet as of December 31, 2021 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company’s financial information. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022 or for any other interim period or for any other future year. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2022 (the “2021 Form 10-K”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: development derivative liability, accrued expenses, prepaid expenses, convertible debt and taxes.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Reference is made to Note 2 Summary of Significant Accounting Policies in our 2021 Form 10-K for a detailed description of significant accounting policies. There have been no significant changes to our accounting policies as disclosed in our 2021 Form 10-K.

Other Comprehensive Income and Accumulated Other Comprehensive Income (Tables)

9 Months Ended

Sep. 30, 2022

Equity [Abstract]

Summary of Changes in Accumulated Other Comprehensive Income/(Loss), by Component

The following tables summarize the changes in accumulated other comprehensive income/(loss), by component for the nine months ended September 30, 2022 and September 30, 2021 (in thousands):


	Unrealized Gains (Losses) from Marketable Securities			Foreign Currency Translation Adjustment			Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2021	$	1		$	(2,091	)	$	(2,090	)
Net other comprehensive income (loss)		(52	)		83			31
Balances, March 31, 2022		(51	)		(2,008	)		(2,059	)
Net other comprehensive loss		(766	)		(369	)		(1,135	)
Balances, June 30, 2022		(817	)		(2,377	)		(3,194	)
Net other comprehensive income (loss)		435			(268	)		167
Balances, September 30, 2022	$	(382	)	$	(2,645	)	$	(3,027	)


	Unrealized Gains (Losses) from Marketable Securities			Foreign Currency Translation Adjustment			Total Accumulated Other Comprehensive Income (Loss)
Balances, December 31, 2020	$	(8	)	$	(109	)	$	(117	)
Net other comprehensive income (loss)		79			(1,582	)		(1,503	)
Balances, March 31, 2021		71			(1,691	)		(1,620	)
Net other comprehensive loss		(35	)		(174	)		(209	)
Balances, June 30, 2021		36			(1,865	)		(1,829	)
Net other comprehensive income (loss)		(25	)		(156	)		(181	)
Balances, September 30, 2021	$	11		$	(2,021	)	$	(2,010	)

Development Liability and Development Derivative Liability - Summary of Development Liability (Detail) - SFJ Agreement [Member] - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development liability	$ 439,500	$ 456,000
Less: Unamortized discount to development liability	(83,212)	(103,265)
Less: Current portion of development liability, net of discount	(16,146)	(7,584)
Total long term development liability	$ 340,142	$ 345,151
Effective Interest Rate	7.91%	7.91%

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2022	Nov. 01, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Registrant Name	APELLIS PHARMACEUTICALS, INC.
Entity Central Index Key	0001492422
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-38276
Entity Tax Identification Number	27-1537290
Entity Address, Address Line One	100 Fifth Avenue
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	617
Local Phone Number	977-5700
Entity Common Stock, Shares Outstanding		110,575,547
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Security 12b Title	Common Stock, $0.0001 par value per share
Trading Symbol	APLS
Security Exchange Name	NASDAQ

Condensed Consolidated Statements of Operations and Comprehensive Income/(Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue:
Revenue	$ 22,056	$ 5,650	$ 52,759	$ 6,273
Operating expenses:
Cost of sales	1,381	149	2,711	149
Research and development	95,207	87,733	287,813	267,688
Cost of research collaboration				50,000
General and administrative	78,406	45,763	192,795	135,309
Total operating expenses:	174,994	133,645	483,319	453,146
Net operating loss	(152,938)	(127,995)	(430,560)	(446,873)
Loss on conversion of debt	(32,890)	(61,102)	(32,890)	(100,589)
Loss from remeasurement of development derivative liability		(4,219)		(42,483)
Interest income	2,809	144	4,339	381
Interest expense	(7,903)	(2,282)	(24,888)	(10,223)
Other income/(expense), net	99	(117)	(42)	1,366
Net loss before taxes	(190,823)	(195,571)	(484,041)	(598,421)
Income tax expense	446	0	2,140	0
Net loss	(191,269)	(195,571)	(486,181)	(598,421)
Other comprehensive gain/(loss):
Unrealized gain/(loss) on marketable securities	435	(25)	(383)	19
Foreign currency loss	(268)	(156)	(554)	(1,912)
Total other comprehensive income/(loss)	167	(181)	(937)	(1,893)
Comprehensive loss, net of tax	$ (191,102)	$ (195,752)	$ (487,118)	$ (600,314)
Net loss per common share, basic	$ (1.75)	$ (2.28)	$ (4.65)	$ (7.31)
Net loss per common share, diluted	$ (1.75)	$ (2.28)	$ (4.65)	$ (7.31)
Weighted-average number of common shares used in net loss per common share, basic	109,126	85,661	104,608	81,846
Weighted-average number of common shares used in net loss per common share, diluted	109,126	85,661	104,608	81,846
Product revenue, net [Member]
Revenue:
Revenue	$ 17,676	$ 5,314	$ 45,439	$ 5,937
Licensing and other revenue [Member]
Revenue:
Revenue	$ 4,380	$ 336	$ 7,320	$ 336

Development Liability and Development Derivative Liability - Schedule of Development Derivative Liability (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance at fair market value	$ 292,132	$ 274,952	$ 257,868	$ 257,868
Amount repaid under the SFJ agreement and SFJ amendment		(4,000)
Loss from remeasurement of development derivative liability	4,219	21,180	17,084	42,483
Balance at fair market value	$ 296,351	$ 292,132	$ 274,952	$ 296,351

Inventory

9 Months Ended

Sep. 30, 2022

Inventory Disclosure [Abstract]

Inventory

4. Inventory

The Company’s inventory of EMPAVELI consisted of the following as of September 30, 2022, and December 31, 2021 (in thousands):


	September 30,		December 31,
	2022		2021
Raw materials	$	25,955	$	5,749
Semi-finished goods		33,124		10,058
Finished goods		674		479
Total Inventories	$	59,753	$	16,286

Product Revenues, Accounts Receivable, and Reserves for Product Sales

9 Months Ended

Sep. 30, 2022

Product Revenues Accounts Receivable And Reserves For Product Sales [Abstract]

Product Revenues, Accounts Receivable, and Reserves for Product Sales

3. Product Revenues, Accounts Receivable, and Reserves for Product Sales

The Company received FDA approval for the sale of EMPAVELI in the United States in May 2021. The Company’s product revenues, net of sales discounts and allowances and reserves, for the three months ended September 30, 2022 and 2021 were $17.7 million and $5.3 million, respectively. The Company’s product revenues, net of sales discounts and allowances and reserves, for the nine months ended September 30, 2022 and 2021 were $45.4 million and $5.9 million, respectively.

The Company’s accounts receivable balance of $8.1 million as of September 30, 2022 and $10.1 million as of December 31, 2021, consisted of EMPAVELI product sales receivable, net of discounts and allowances of $0.3 million and $0.2 million, respectively. The Company does not have a reserve against its receivable balance.

The Company’s product sales reserves totaled $2.0 million and $1.0 million as of September 30, 2022 and December 31, 2021, respectively. These amounts are included in accrued expenses on the Company’s unaudited condensed consolidated balance sheet.

Fair Value Measurements - Schedule of Financial Instruments and the Related Fair Value Hierarchy of the Valuation Techniques Utilized (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	$ 124,364	$ 60,358
Marketable Securities [Member] \| US Government Obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	124,364	60,358
Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	124,364	60,358
Level 1 [Member] \| Marketable Securities [Member] \| US Government Obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Financial Assets	$ 124,364	$ 60,358

Income Taxes

9 Months Ended

Sep. 30, 2022

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

For the three and nine months ended September 30, 2022, the Company recorded $0.4 million and $2.1 million of income tax expense, respectively, primarily pertaining to federal and state income taxes where the utilization of net operating losses and research and development tax credits are limited. There was no income tax provision for the three months and nine months ended September 30, 2021.

The income tax provision during interim periods is computed by applying an estimated annual effective tax rate to year-to-date pre-tax income, plus adjustments for significant unusual or infrequently occurring items, in accordance with FASB ASC Topic 740-270, Income Taxes – Interim Reporting. The income tax provision differs from the U.S. federal statutory rate of 21% primarily due to the effect of valuation allowance against the Company’s net deferred tax assets, which reduces the Company’s net tax benefit.

Deferred tax assets and deferred tax liabilities are determined based on temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company has recorded a full valuation allowance against its net deferred tax assets for the period ended September 30, 2022.

The Company does not recognize a tax benefit for uncertain tax positions unless it is more likely than not that the position will be sustained upon examination by tax authorities, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The tax benefit that is recorded for these positions is measured at the largest amount of cumulative benefit that has greater than a 50 percent likelihood of being realized upon ultimate settlement. Deferred tax assets that do not meet these recognition criteria are not recorded and the Company recognizes a liability for uncertain tax positions that may result in tax payments. The Company recorded $1.9 million of unrecognized tax benefits for the period ended September 30, 2022. If such unrecognized tax benefits were realized, the entire amount would impact the tax provision. Our policy is to review and update unrecognized tax positions as facts and circumstances change.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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+ Details

Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Lessee Lease Description [Line Items]
Operating lease description			The Company enters into lease agreements with terms generally ranging from 2-7 years. Some of the Company’s lease agreements include Company options to extend the lease on a month-to-month basis or for set periods for up to five years. Many of these leases also include options to terminate the leases within one year or per other contractual terms. Renewal and termination options were generally not included in the lease term for the Company’s existing operating leases.
Operating lease, existence of option to extend			true
Operating lease maximum term of options to terminate lease			1 year
Operating lease expense	$ 1.7	$ 1.4	$ 4.6	$ 4.2
Minimum [Member]
Lessee Lease Description [Line Items]
Operating lease, term of contract	2 years		2 years
Maximum [Member]
Lessee Lease Description [Line Items]
Operating lease, term of contract	7 years		7 years
Operating lease options to extend lease	5 years		5 years

Long-term Debt

9 Months Ended

Sep. 30, 2022

Debt Disclosure [Abstract]

Long-term Debt

7. Long-term Debt

Convertible Senior Notes

On September 16, 2019, the Company completed a private offering of convertible notes (the “2019 Convertible Notes”) with an aggregate principal amount of $220.0 million issued pursuant to an indenture (the “Indenture”) with U.S. Bank National Association, as trustee.

The net proceeds from the sale of the 2019 Convertible Notes were approximately $212.9 million after deducting the initial purchasers’ discounts and commissions of $6.6 million and offering expenses of $0.5 million by the Company. The Company used $28.4 million of the net proceeds from the sale of the 2019 Convertible Notes to pay the cost of the capped call transactions in September 2019 described below.

On May 12, 2020, the Company issued convertible notes (the “2020 Convertible Notes”) with an aggregate principal amount of $300.0 million. The net proceeds from the sale of the 2020 Convertible Notes were approximately $322.9 million after deducting the purchasers’ discounts and commission of $5.7 million and offering expenses of $0.3 million. The Company used $43.1 million of the net proceeds from the sale to pay the cost of the additional capped call transactions in May 2020 described below.

The 2019 Convertible Notes and the 2020 Convertible Notes are referred to together as the Convertible Notes. The Convertible Notes are senior unsecured obligations of the Company and bear interest at a rate of 3.5% per year payable semiannually in arrears on March 15 and September 15 of each year, beginning on March 15, 2020. The Convertible Notes will mature on September 15, 2026, unless converted earlier, redeemed or repurchased in accordance with their terms.

The Convertible Notes are convertible into shares of the Company’s common stock at an initial conversion rate of 25.3405 shares per $1,000 principal amount of Convertible Notes (equivalent to an initial conversion price of approximately $39.4625 per share of common stock). The conversion rate is subject to customary anti-dilution adjustments. In addition, following certain events that occur prior to the maturity date or if the Company delivers a notice of redemption, the Company will increase the conversion rate for a holder who elects to convert its Convertible Notes in connection with such corporate event or a notice of redemption, as the case may be, in certain circumstances as provided in the Indenture.

Prior to March 15, 2026, the Convertible Notes are convertible only under the following circumstances:

•

during any calendar quarter, if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day;

•

during the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of the Convertible Notes for each such trading day was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day;

•

if the Company calls any or all of the Convertible Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or

•

upon the occurrence of corporate events specified in the Indenture.

On or after March 15, 2026 until the close of business on the second scheduled trading day immediately preceding the maturity date of the Convertible Notes, holders may convert the Convertible Notes at any time regardless of the foregoing circumstances. Upon conversion of the Convertible Notes, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of common stock, at the Company’s election.

Prior to September 20, 2023, the Company may not redeem the Convertible Notes. The Company may redeem for cash all or a portion of the Convertible Notes, at its option, on or after September 20, 2023 if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive), including the trading day immediately preceding the date on which the Company provides a notice of redemption, during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption. The redemption price will be equal to 100% of the principal amount of the Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.

If the Company undergoes a “fundamental change,” as defined in the Indenture, prior to maturity, subject to certain conditions, holders may require the Company to repurchase for cash all or any portion of their Convertible Notes at a fundamental change repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

The Company used an effective interest rate of 10.5% to determine the liability component of the 2019 and 2020 Convertible Notes. This resulted in the recognition of $145.1 million and $204.5 million as the liability component of the 2019 and 2020 Convertible Notes, respectively, and the recognition of the residual amount of $74.9 million and $95.5 million as the debt discount with a corresponding increase to additional paid in capital for the equity component of the 2019 and 2020 Convertible Notes, respectively. The 2020 Convertible Notes aggregate debt issuance costs of $6.0 million were allocated to the liability and equity components in the

amounts of $3.7 and $2.3 million, respectively. The 2019 Convertible Notes aggregate debt issuance costs of $7.1 million were allocated to the liability and equity components in the amounts of $4.7 million and $2.4 million, respectively.

Effective January 1, 2021, the Company adopted ASU 2020-06 using the modified retrospective method. Upon adoption, the Company increased net debt and reduced net equity by $149.7 million. The $149.7 million consisted of several items. The first item is the reclassification from equity to debt of the residual amounts originally identified as the equity components of the 2019 and 2020 Convertible Notes of $74.9 million and $95.5 million, respectively. The equity component reclassification was offset by the adjustment to retained earnings for the reversal of previous non-cash interest expense recorded for the amortization of the equity components of $17.1 million. The second item is the reclassification from equity to debt of the debt issuance costs originally allocated to equity for the 2019 and 2020 Convertible Notes of $2.4 million and $2.3 million, respectively. The debt issuance costs reclassification was offset by the adjustment to retained earnings for previous amortization of the debt issuance costs recorded of $1.1 million.

In January 2021, July 2021 and July 2022, the Company entered into separate, privately negotiated exchange agreements to modify the conversion terms with certain holders of its 2019 Convertible Notes and 2020 Convertible Notes. Under the terms of these exchange agreements, in January 2021, July 2021 and July 2022, the holders exchanged approximately $126.1 million of 2019 Convertible Notes, $201.1 million of 2019 Convertible Notes and 2020 Convertible Notes, and $98.1 million of 2020 Convertible Notes, respectively, in aggregate principal amount held by them for an aggregate of 3,906,869 shares, 5,992,217 shares and 3,027,018 shares, respectively, of common stock issued by the Company. In accordance with FASB ASC Topic 470-20, “Debt – Debt with Conversion and Other Options,” (“ASC 470-20”) the Company accounted for the exchange as an induced conversion based on the short period of time the conversion offer was open and the substantive conversion feature offer. The Company accounted for the conversion of the debt as an inducement by expensing the fair value of the shares that were issued in excess of the original terms of the Convertible Notes.

As a result of the January 2021 exchange transactions, the Company reduced net debt outstanding and increased net equity on the consolidated balance sheet by $122.8 million, consisting of the par value of the 2019 Convertible Notes exchanged of $126.1 million less the $3.3 million of remaining debt issuance costs associated with the exchanged notes. The Company also increased shares outstanding by 3,906,869 shares consisting of 3,196,172 shares issued at the initial conversion rate in the Indenture of 25.3405 plus an additional 710,697 shares. Additionally, the Company issued 69,491 shares as settlement of debt issuance costs paid to the Company’s financial advisor in connection with the exchange transaction. For the three months ended March 31, 2021, the Company recorded a loss on conversion of debt of $39.5 million comprised of $36.4 million related to the value of the shares issued in excess of the original conversion terms at the fair market value and $3.1 million for the value of the 69,491 shares issued in payment of issuance costs at their then fair value. Upon exchange of the 2019 Convertible Notes, the holders forfeited accrued interest through the date of the exchange of $1.7 million, which the Company charged to interest expense and to equity.

As a result of the July 2021 exchange transactions, the Company reduced net debt outstanding and increased net equity on the consolidated balance sheet by $197.0 million, consisting of the par value of the Convertible Notes exchanged of $201.1 million less the $4.1 million of remaining debt issuance costs associated with the exchanged notes. The Company also increased shares outstanding by 5,992,217 shares consisting of 5,097,166 shares issued at the initial conversion rate in the Indenture of 25.3405 plus an additional 895,051 shares. Additionally, the Company issued 78,419 shares as settlement of issuance costs paid to the Company’s financial advisor in connection with the exchange transaction. For the three months ended September 30, 2021, the Company recorded a loss on conversion of debt of $61.1 million comprised of $55.9 million related to the value of the shares issued in excess of the original conversion terms at the fair market value and $5.2 million for the value of the 78,419 shares issued in payment of issuance costs at their then fair value. Upon exchange of the Convertible Notes, the holders forfeited accrued interest through the date of the exchange of $2.5 million, which the Company charged to interest expense and to equity.

As a result of the July 2022 transactions, the Company reduced net debt outstanding and increased net equity on the consolidated balance sheet by $96.8 million, consisting of the par value of the Convertible Senior Notes exchanged of $98.1 million less the $1.3 million of remaining debt issuance costs associated with the exchanged notes. The Company also increased shares outstanding by 3,027,018 shares consisting of 2,485,548 shares issued at the initial conversion rate in the Indenture of 25.3405 plus an additional 541,470 shares. Additionally, the Company issued 46,132 shares as settlement of issuance costs paid to the Company’s financial advisor in connection with the exchange transaction. For the three months ended September 30, 2022, the Company recorded a loss on conversion of debt of $32.9 million comprised of $30.4 million related to the value of the shares issued in excess of the original conversion terms at the fair market value and $2.5 million for the value of the 46,132 shares issued in payment of issuance costs at their then fair value. Upon exchange of the Convertible Notes, the holders forfeited accrued interest through the date of the exchange of $1.3 million, which the Company charged to interest expense and to equity.

The conditional conversion feature of the Convertible Notes was triggered as of June 30, 2021, and as a result the Convertible Notes were convertible at the option of the holders until September 30, 2021. During this period, certain holders of the Convertible Notes

converted approximately $0.7 million of aggregate principal amount of Convertible Notes into an aggregate of 18,775 shares, which were issued in October 2021.

The conditional conversion feature of the Convertible Notes was again triggered as of September 30, 2022, and as a result the Convertible Notes became convertible at the option of the holders. No Convertible Notes were converted through the date of issuance of these unaudited condensed consolidated financial statements.

As of September 30, 2022, the Company held in treasury Convertible Notes in principal amount of $425.4 million which notes had not been cancelled.

Interest expense for the Convertible Notes was $1.2 million and $4.8 million for the three and nine months ended September 30, 2022, respectively. For the three months ended September 30, 2022, interest expense included accrued semi-annual coupon payable of $1.1 million and amortization of debt issuance costs of $0.1 million. For the nine months ended September 30, 2022, interest expense included accrued semi-annual coupon payable of $4.4 million and amortization of debt issuance costs of $0.4 million. As of September 30, 2022 and December 31, 2021, $1.2 million and $3.0 million, respectively, of debt issuance costs were recorded in the unaudited condensed consolidated balance sheet as a reduction to the carrying amount of the Convertible Notes.

Interest expense for the Convertible Notes was $2.3 million and $10.2 million for the three and nine months ended September 30, 2021, respectively. For the three months ended September 30, 2021, interest expense included accrued semi-annual coupon payable of $2.1 million and amortization of debt issuance costs of $0.2 million. For the nine months ended September 30, 2021, interest expense included accrued semi-annual coupon payable of $9.4 million and amortization of debt issuance costs of $0.8 million. As of September 30, 2021, $3.1 million of debt issuance costs was recorded in the unaudited condensed consolidated balance sheet as a reduction to the carrying amount of the Convertible Notes.

The aggregate principal balance of the Convertible Notes held by third parties, net of unamortized debt issuance costs, as of September 30, 2022 and December 31, 2021 was $92.7 million and $189.0 million respectively.

Capped Call Transactions

On September 11, 2019 and May 6, 2020, concurrently with the pricing of the Convertible Notes, the Company entered into capped call transactions with two counterparties. The capped call transactions are expected generally to reduce the potential dilution to the Company’s common stock upon any conversion of Convertible Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted Convertible Notes, as the case may be, in the event that the market price per share of the Company’s common stock, as measured under the terms of the capped call transactions, is greater than the strike price of the capped call transactions, which is initially $39.4625 (the conversion price of the Convertible Notes) and is subject to anti-dilution adjustments substantially similar to those applicable to the conversion rate of such Convertible Notes. If, however, the market price per share of the Company’s common stock, as measured under the terms of the capped call transactions, exceeds the cap price of the capped call transactions, which is initially $63.14 per share, representing a premium of 100% above the last reported sale price of $31.57 per share of its common stock on The Nasdaq Global Select Market on September 11, 2019, there would nevertheless be dilution and/or there would not be an offset of such potential cash payments, in each case, to the extent that such market price exceeds the cap price of the capped call transactions.

Pursuant to FASB ASC Topic 815-40 Derivatives and Hedging, the Company determined that the capped call transactions should be classified as equity instruments and the capped call premium paid in the amount of $28.4 million and $43.1 million were recorded as reductions to additional paid-in capital at December 31, 2021 for the 2019 Convertible Notes and the 2020 Convertible Notes, respectively.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-URI https://asc.fasb.org/topic&trid=2208564

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+ Details

Basis of Presentation and Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2022

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted and, accordingly, the consolidated balance sheet as of December 31, 2021 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company’s financial information. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022 or for any other interim period or for any other future year.

The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2022 (the “2021 Form 10-K”).

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: development derivative liability, accrued expenses, prepaid expenses, convertible debt and taxes.

Summary of Significant Accounting Policies

Reference is made to Note 2 Summary of Significant Accounting Policies in our 2021 Form 10-K for a detailed description of significant accounting policies. There have been no significant changes to our accounting policies as disclosed in our 2021 Form 10-K.

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating Activities
Net loss	$ (486,181)	$ (598,421)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	66,844	51,355
Loss on conversion of debt	32,890	100,589
Loss from remeasurement of development derivative liability		42,483
Forfeiture of accrued interest in exchange of convertible notes	1,287	4,171
Amortization of right-of-use assets	(105)	110
Depreciation expense	1,164	1,006
Amortization of discounts for convertible notes, net of financing costs	386	821
Accretion of discount to development liability	20,053
Other liabilities	1,938
Changes in operating assets and liabilities:
Accounts receivable	2,010	(2,618)
Inventory	(43,436)	(1,677)
Prepaid assets	(5,492)	(5,862)
Other current assets	45,457	6,677
Other assets	15,885	(3,956)
Accounts payable	(4,437)	(3,213)
Accrued expenses	(21,264)	(42,092)
Net cash used in operating activities	(373,001)	(450,627)
Investing Activities
Purchase of property and equipment	(673)	(1,084)
Purchase of available-for-sale securities	(331,863)	(171,280)
Proceeds from maturity of available-for-sale securities	268,300	335,000
Net cash (used in) provided by investing activities	(64,236)	162,636
Financing Activities
Proceeds from issuance of common stock, net of issuance costs	380,120
Payments for development derivative liability		(4,000)
Payments for development liability	(16,500)
Proceeds from exercise of stock options	19,409	12,131
Proceeds from issuance of common stock under employee share purchase plan	2,531	1,698
Payments of employee tax withholding related to equity-based compensation	(3,955)	(1,551)
Net cash provided by financing activities	381,605	8,278
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(675)	(2,024)
Net decrease in cash, cash equivalents and restricted cash	(56,307)	(281,737)
Cash, cash equivalents and restricted cash at beginning of period	641,755	567,045
Cash, cash equivalents and restricted cash at end of period	585,448	285,308
Reconciliation of cash, cash equivalents and restricted cash to the consolidated balance sheets:
Cash and cash equivalents	584,189	283,745
Restricted cash	1,259	1,563
Total cash, cash equivalents, and restricted cash	585,448	285,308
Supplemental Disclosure of Financing Activities
Cash paid for interest	5,003	10,265
Cash paid for income taxes	156
Convertible Notes exchanged for common stock	$ 98,086	$ 327,276

Prepaid Assets and Accrued Expenses

9 Months Ended

Sep. 30, 2022

Prepaid Assets And Accrued Expenses [Abstract]

Prepaid Assets And Accrued Expenses

5. Prepaid Assets and Accrued Expenses

Prepaid assets include $16.0 million and $12.0 million of prepaid research and development costs as of September 30, 2022 and December 31, 2021, respectively.

Accrued expenses are as follows (in thousands):


	September 30,		December 31,
	2022		2021
Accrued research and development	$	28,071	$	35,217
Accrued cost of research collaboration		—		25,000
Accrued license fee		—		5,000
Accrued royalties		723		—
Accrued payroll liabilities		33,467		25,212
Other		17,517		12,810
Total	$	79,778	$	103,239

Fair Value Measurements

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

11. Fair Value Measurements

The Company is required to disclose information on the fair value of financial instruments and inputs that enable an assessment of the fair value. The three levels of the fair value hierarchy prioritize valuation inputs based upon the observable nature of those inputs as follows:

Level 1 – Quoted prices in active markets for identical assets or liabilities;

Level 2 – Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly;

Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability.

The following table presents the fair value of financial instruments recorded originally at amortized cost or fair value and not remeasured on a recurring basis (in thousands):


		September 30, 2022
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Cash and cash equivalents:	Money market funds	$	540,297	$	—	$	—	$	540,297
Total Financial Assets		$	540,297	$	—	$	—	$	540,297

		December 31, 2021
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Cash and cash equivalents	Money market funds	$	598,833	$	—	$	—	$	598,833
Total Financial Assets		$	598,833	$	—	$	—	$	598,833

The following table presents the fair value of financial instruments recorded at fair value at inception and remeasured on a recurring basis (in thousands):


		September 30, 2022
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Marketable securities:	US government obligations	$	124,364		—		—	$	124,364
Total Financial Assets		$	124,364	$	—	$	—	$	124,364

		December 31, 2021
Balance Sheet Classification	Type of Instrument	Level 1		Level 2		Level 3		Total
Financial Assets:
Marketable securities:	US government obligations	$	60,358	$	—	$	—	$	60,358
Total Financial Assets		$	60,358	$	—	$	—	$	60,358

The Company's Convertible Notes and development liability are financial instruments that are reported in the consolidated financial statements at historical cost. The Convertible Notes are Level 1 within the fair value level hierarchy as of September 30, 2022 and December 31, 2021. The fair value of the Convertible Notes was $177.5 million as of September 30, 2022 and $290.7 million as of December 31, 2021. The Convertible Notes accrue a semi-annual coupon at an annual rate of 3.5%, which was included in accrued expenses in the consolidated balance sheets as of September 30, 2022 and December 31, 2021.

The fair value of the development liability was $320.0 million and $352.7 million as of September 30, 2022 and December 31, 2021, respectively. The development liability is Level 2 within the fair value hierarchy based on the discounting of fixed cash flows using an observed bond yield for borrowers with similar credit rating.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Product Revenues, Accounts Receivable, and Reserves for Product Sales - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Product Revenues Accounts Receivable And Reserves For Product Sales [Line Items]
Revenue	$ 22,056	$ 5,650	$ 52,759	$ 6,273
Accounts receivable	8,091		8,091		$ 10,103
Accounts receivable, net of discount and allowance	300		300		200
Accrued Expenses [Member]
Product Revenues Accounts Receivable And Reserves For Product Sales [Line Items]
Product sales reserves	2,000		2,000		$ 1,000
Product [Member]
Product Revenues Accounts Receivable And Reserves For Product Sales [Line Items]
Revenue	$ 17,676	$ 5,314	$ 45,439	$ 5,937

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Condensed Consolidated Statements of Changes in Stockholder's Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning balance at Dec. 31, 2020	$ 204,557	$ (149,734)	$ 8	$ 1,131,013	$ (165,747)	$ (117)	$ (926,347)	$ 16,013
Beginning balance, Shares at Dec. 31, 2020			76,130,000
Accounting Standards Update description	ASU 2020-06
Issuance of shares in exchange of Convertible Notes , including issuance costs	$ 162,258			162,258
Issuance of shares in exchange of Convertible Notes, including issuance costs, shares			3,976,000
Forfeiture of accrued interest in exchange of Convertible Notes	1,668			1,668
Issuance of common stock upon exercise of stock options	2,588			2,588
Issuance of common stock upon exercise of stock options, shares			285,000
Vesting of restricted stock units, net of shares withheld for taxes	(956)			(956)
Vesting of restricted stock units, net of shares withheld for taxes. shares			47,000
Share-based compensation expense	16,439			16,439
Unrealized gain (loss) on available-for-sale investments	79					79
Net loss	(183,659)						(183,659)
Foreign currency gain (loss)	(1,582)					(1,582)
Ending balance at Mar. 31, 2021	51,658		$ 8	1,147,263		(1,620)	(1,093,993)
Ending balance, Shares at Mar. 31, 2021			80,438,000
Beginning balance at Dec. 31, 2020	204,557	$ (149,734)	$ 8	1,131,013	$ (165,747)	(117)	(926,347)	$ 16,013
Beginning balance, Shares at Dec. 31, 2020			76,130,000
Unrealized gain (loss) on available-for-sale investments	19
Net loss	(598,421)
Foreign currency gain (loss)	(1,912)
Ending balance at Sep. 30, 2021	(57,325)		$ 9	1,453,431		(2,010)	(1,508,755)
Ending balance, Shares at Sep. 30, 2021			87,219,000
Beginning balance at Mar. 31, 2021	51,658		$ 8	1,147,263		(1,620)	(1,093,993)
Beginning balance, Shares at Mar. 31, 2021			80,438,000
Issuance of common stock upon exercise of stock options	7,062			7,062
Issuance of common stock upon exercise of stock options, shares			444,000
Vesting of restricted stock units, net of shares withheld for taxes	(233)			(233)
Vesting of restricted stock units, net of shares withheld for taxes. shares			11,000
Share-based compensation expense	17,722			17,722
Issuance of common stock to employee stock purchase plan	1,698			1,698
Issuance of common stock to employee stock purchase plan, shares			63,000
Unrealized gain (loss) on available-for-sale investments	(35)					(35)
Net loss	(219,191)						(219,191)
Foreign currency gain (loss)	(174)					(174)
Ending balance at Jun. 30, 2021	(141,493)		$ 8	1,173,512		(1,829)	(1,313,184)
Ending balance, Shares at Jun. 30, 2021			80,956,000
Issuance of shares in exchange of Convertible Notes , including issuance costs	258,105		$ 1	258,104
Issuance of shares in exchange of Convertible Notes, including issuance costs, shares			6,071,000
Forfeiture of accrued interest in exchange of Convertible Notes	2,503			2,503
Issuance of common stock upon exercise of stock options	2,480			2,480
Issuance of common stock upon exercise of stock options, shares			177,000
Vesting of restricted stock units, net of shares withheld for taxes	(362)			(362)
Vesting of restricted stock units, net of shares withheld for taxes. shares			15,000
Share-based compensation expense	17,194			17,194
Unrealized gain (loss) on available-for-sale investments	(25)					(25)
Net loss	(195,571)						(195,571)
Foreign currency gain (loss)	(156)					(156)
Ending balance at Sep. 30, 2021	(57,325)		$ 9	1,453,431		(2,010)	(1,508,755)
Ending balance, Shares at Sep. 30, 2021			87,219,000
Beginning balance at Dec. 31, 2021	198,662		$ 10	1,857,430		(2,090)	(1,656,688)
Beginning balance, Shares at Dec. 31, 2021			97,524,000
Common Stock -follow-on-offering	380,120		$ 1	380,119
Common Stock -follow-on-offering, shares			8,564,000
Issuance of common stock upon exercise of stock options	4,000			4,000
Issuance of common stock upon exercise of stock options, shares			239,000
Vesting of restricted stock units, net of shares withheld for taxes	(2,416)			(2,416)
Vesting of restricted stock units, net of shares withheld for taxes. shares			113,000
Share-based compensation expense	20,773			20,773
Unrealized gain (loss) on available-for-sale investments	(52)					(52)
Net loss	(138,935)						(138,935)
Foreign currency gain (loss)	83					83
Ending balance at Mar. 31, 2022	462,235		$ 11	2,259,906		(2,059)	(1,795,623)
Ending balance, Shares at Mar. 31, 2022			106,440,000
Beginning balance at Dec. 31, 2021	198,662		$ 10	1,857,430		(2,090)	(1,656,688)
Beginning balance, Shares at Dec. 31, 2021			97,524,000
Unrealized gain (loss) on available-for-sale investments	(383)
Net loss	(486,181)
Foreign currency gain (loss)	(554)
Ending balance at Sep. 30, 2022	307,416		$ 11	2,453,301		(3,027)	(2,142,869)
Ending balance, Shares at Sep. 30, 2022			110,476,000
Beginning balance at Mar. 31, 2022	462,235		$ 11	2,259,906		(2,059)	(1,795,623)
Beginning balance, Shares at Mar. 31, 2022			106,440,000
Issuance of common stock upon exercise of stock options	4,770			4,770
Issuance of common stock upon exercise of stock options, shares			283,000
Vesting of restricted stock units, net of shares withheld for taxes	(536)			(536)
Vesting of restricted stock units, net of shares withheld for taxes. shares			26,000
Share-based compensation expense	22,530			22,530
Issuance of common stock to employee stock purchase plan	2,531			2,531
Issuance of common stock to employee stock purchase plan, shares			92,000
Unrealized gain (loss) on available-for-sale investments	(766)					(766)
Net loss	(155,977)						(155,977)
Foreign currency gain (loss)	(369)					(369)
Ending balance at Jun. 30, 2022	334,418		$ 11	2,289,201		(3,194)	(1,951,600)
Ending balance, Shares at Jun. 30, 2022			106,841,000
Issuance of shares in exchange of Convertible Notes , including issuance costs	129,636			129,636
Issuance of shares in exchange of Convertible Notes, including issuance costs, shares			3,073,000
Forfeiture of accrued interest in exchange of Convertible Notes	1,287			1,287
Issuance of common stock upon exercise of stock options	10,639			10,639
Issuance of common stock upon exercise of stock options, shares			521,000
Vesting of restricted stock units, net of shares withheld for taxes	(1,003)			(1,003)
Vesting of restricted stock units, net of shares withheld for taxes. shares			41,000
Share-based compensation expense	23,541			23,541
Unrealized gain (loss) on available-for-sale investments	435					435
Net loss	(191,269)						(191,269)
Foreign currency gain (loss)	(268)					(268)
Ending balance at Sep. 30, 2022	$ 307,416		$ 11	$ 2,453,301		$ (3,027)	$ (2,142,869)
Ending balance, Shares at Sep. 30, 2022			110,476,000

Prepaid Assets and Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Prepaid Assets And Accrued Expenses [Abstract]
Accrued research and development	$ 28,071	$ 35,217
Accrued cost of research collaboration		25,000
Accrued license fee		5,000
Accrued royalties	723
Accrued payroll liabilities	33,467	25,212
Other	17,517	12,810
Total	$ 79,778	$ 103,239