Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 75,970	$ 153,001
Marketable securities	160,183	94,776
Accounts receivable	0	47
Prepaid expenses and other current assets (includes $0 and $285 at March 31, 2022 and December 31, 2021, respectively, attributable to related parties)	6,894	8,456
Total current assets	243,047	256,280
Marketable securities, long-term	48,362	67,652
Property and equipment, net	18,456	14,391
Operating lease right-of-use assets	14,186	14,562
Other assets	875	602
Total assets	324,926	353,487
Current liabilities
Accounts payable	2,681	4,764
Accrued and other current liabilities	5,264	7,744
Deferred revenue	2,109	2,599
Operating lease liabilities, current portion	2,037	1,231
Total current liabilities	12,091	16,338
Deferred revenue, net of current portion	1,761	2,491
Derivative liability	221	214
Long-term portion of operating lease liabilities	14,782	15,217
Other liabilities	15	120
Total liabilities	28,870	34,380
Commitments and contingencies (Note 9)
Stockholders’ equity
Common stock, $0.0001 par value, 300,000,000 shares authorized at March 31, 2022 and December 31, 2021; 32,264,065 and 32,224,524 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	3	3
Additional paid-in-capital	530,808	526,523
Accumulated other comprehensive loss	(1,421)	(423)
Accumulated deficit	(233,334)	(206,996)
Total stockholders’ equity	296,056	319,107
Total liabilities and stockholders’ equity	$ 324,926	$ 353,487