Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (166,183)	$ (65,009)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	29,646	24,368
Depreciation and amortization	6,958	6,302
Provision for credit losses	5,532	7,678
Net amortization of premiums on marketable debt securities	4,377	586
Net losses (gains) on investments	(5,189)	8,207
Imputed interest income from licensing	(341)	(2,033)
Non-cash interest expense	19,777
Other non-cash adjustments	(51)	263
Changes in operating assets and liabilities
Accounts receivable	(7,886)	(89,442)
Prepaid expenses	(7,896)	(9,637)
Other current assets	(3,307)	(2,998)
Operating lease right-of-use assets	3,780	1,986
Other assets	(4,402)	1,318
Accounts payable	6,503	9,907
Accrued expenses and other current liabilities	473	18,400
Operating lease liabilities	10,849	(2,222)
Other liabilities	(2)	(1,203)
Net cash used in operating activities	(107,362)	(93,529)
Cash flows from investing activities
Purchases of marketable debt securities	(262,671)	(79,374)
Maturities of marketable debt securities	136,386	189,882
Sales of marketable debt securities		2,287
Sales of equity securities	5,563	12,374
Purchases of property and equipment	(69,561)	(13,980)
Net cash provided by (used in) investing activities	(190,283)	111,189
Cash flows from financing activities
Proceeds from exercise of stock options	3,296	4,247
Proceeds from issuance of common stock under employee stock purchase plan	1,768	1,799
Proceeds from public offering of common stock, net of underwriting discounts and commissions	216,438
Issuance costs for public offering of common stock	(379)
Repayments under liability related to sale of future royalties	(33,252)
Transaction costs for sale of future royalties	(265)
Net cash provided by financing activities	187,606	6,046
Net increase (decrease) in cash and cash equivalents and restricted cash	(110,039)	23,706
Cash and cash equivalents and restricted cash
Beginning of period	339,756	70,844
End of period	229,717	94,550
Supplemental disclosures of non-cash investing and financing activities
Net additions to property and equipment through accounts payable and accrued expenses	3,250	46
Non-cash additions to property and equipment through tenant improvement allowance		2,217
Non-cash consideration received for licenses granted		$ 1,123
Proceeds due to Company from sales of non-marketable equity securities	$ 646