Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net (loss) income	$ (67,413)	$ 27,416
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	3,529	3,125
Amortization of premium on marketable securities	1,982	293
Stock-based compensation	16,354	8,830
Noncash lease expenses	3,841
Unrealized loss (gain) on equity securities	1,881	(78,638)
Remeasurement of liability awards	73	3,165
Other	406	558
Changes in operating assets and liabilities:
Accounts receivable	(6,771)	(1,185)
Prepaid expenses and other assets	(4,534)	823
Accounts payable	4,484	(716)
Accrued compensation	(336)	(127)
Other liabilities	629	(747)
Deferred rent		(129)
Deferred revenue	(12,754)	(11,591)
Change in operating lease liability	(1,470)
Net cash used in operating activities	(60,099)	(48,923)
Investing activities
Purchases of marketable securities	(226,109)	(113,999)
Maturities of marketable securities	106,750	82,300
Sales of marketable securities	14,049	22,000
Purchases of equipment and leasehold improvements	(12,786)	(5,504)
Net cash used in investing activities	(118,096)	(15,203)
Financing activities
Proceeds from public offering		115,438
Payment of issuance costs		(7,188)
Proceeds from debt refinancing		25,000
Payment of debt		(10,000)
Proceeds from exercise of common stock options	1,972	172
Taxes paid related to net shares settlement of restricted stock units	(987)	(314)
Proceeds from employee stock purchase plan	1,765	1,285
Net cash provided by financing activities	2,750	124,393
Net (decrease) increase in cash, cash equivalents and restricted cash	(175,445)	60,267
Cash, cash equivalents and restricted cash at beginning of period	207,024	4,975
Cash, cash equivalents and restricted cash at end of period	31,579	65,242
Supplemental disclosure of cash flow information:
Cash paid for interest	1,536	1,165
Supplemental disclosure of non-cash investing and financing information:
Purchases of equipment included in accounts payable	2,165	11
Embedded interest associated with program fees	561	1,544
Warrants issued to lenders		$ 619
Remeasurement of operating lease right-of-use assets for lease modification	$ 4,227