Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows used in operating activities:
Net loss	$ (20,971)	$ (11,912)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:
Depreciation expense	451	416
Stock-based compensation expense	3,845	116
Accretion of discount on marketable securities	102
Reduction in carrying amount of right-of-use assets	320	298
Amortization of debt discount	182
Changes in operating assets and liabilities:
Accounts receivable	828	1,303
Prepaid expenses and other current assets	(40)	(281)
Accounts payable	(1,965)	(2,100)
Accrued expenses and other current liabilities	(3,666)	(1,298)
Operating lease liability	(251)	(212)
Deferred revenue	(3,769)	(2,996)
Net cash used in operating activities	(24,934)	(16,666)
Cash flows used in investing activities:
Sales and maturities of marketable securities	114,994
Purchases of marketable securities	(176,303)
Purchases of property and equipment	(421)	(184)
Net cash used in investing activities	(61,730)	(184)
Cash flows (used in) provided by financing activities:
Proceeds from exercises of stock options	166	156
Payment of initial public offering costs	(314)
Other	(3)
Net cash (used in) provided by financing activities	(151)	156
Net change in cash, cash equivalents and restricted cash	(86,815)	(16,694)
Cash, cash equivalents and restricted cash at beginning of period	184,304	93,126
Cash, cash equivalents and restricted cash at end of period	97,489	76,432
Reconciliation of cash, cash equivalents and restricted cash:
Cash, cash equivalents and restricted cash at end of period	97,489	76,432
Less: restricted cash	(2,577)	(2,577)
Cash and cash equivalents at end of the period	94,912	73,855
Supplemental disclosures of cash flow information:
Cash paid for interest	358
Supplemental disclosures of non-cash investing and financing activities:
Capital expenditures in accounts payable and accrued expenses	$ 722	12
Stock option repurchases included in accrued expenses		202
Vested stock option liability included in accrued expenses		$ 728