Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 281,146	$ 181,727
Marketable securities, current	184,765	189,962
Accounts receivable	6,213	4,484
Prepaid expenses and other current assets	5,437	4,836
Total current assets	477,561	381,009
Marketable securities, non-current	32,770
Property and equipment, net	3,653	3,323
Right-of-use asset	12,582	13,229
Restricted cash	1,276	2,577
Other assets	579
Total assets	528,421	400,138
Current liabilities:
Accounts payable	4,469	5,683
Accrued expenses and other current liabilities	9,871	9,524
Deferred revenue, current	28,695	27,603
Operating lease liability, current	1,131	1,042
Total current liabilities	44,166	43,852
Deferred revenue, net of current	46,189	53,617
Operating lease liability, net of current	11,230	11,826
Long-term debt − related party	10,409	10,052
Total liabilities	111,994	119,347
Commitments and contingencies
Stockholders’ equity:
Preferred stock, par value of $0.0001 per share; 10,000,000 shares authorized, and no shares issued or outstanding as of June 30, 2021 and December 31, 2020, respectively
Common stock, par value of $0.0001 per share; 150,000,000 shares authorized, and 48,380,059 and 43,059,632 shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively	5	4
Additional paid-in capital	643,865	464,597
Accumulated other comprehensive (loss) income	(69)	13
Accumulated deficit	(227,374)	(183,823)
Total stockholders’ equity	416,427	280,791
Total liabilities and stockholders’ equity	$ 528,421	$ 400,138