Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 183,403	$ 486,055
Marketable securities	141,815	26,573
Restricted cash	64	565
Prepaid expenses and other current assets	6,498	9,129
Total current assets	331,780	522,322
Property and equipment, net	5,320	5,534
Operating lease right-of-use assets	5,477	10,550
Other assets	1,080	1,027
Total assets	343,657	539,433
Current liabilities
Accounts payable	3,244	7,508
Accrued research and development expenses	16,205	10,431
Accrued expenses and other current liabilities	20,410	20,711
Total current liabilities	39,859	38,650
Long-term convertible senior notes	150,038	143,642
Long-term debt	29,079	28,744
Operating lease liabilities - long-term	3,218	7,713
Total liabilities	222,194	218,749
Commitments and contingencies
Stockholders' equity (deficit)
Common stock, $0.0001 par value; 700,000,000 shares authorized as of December 31, 2021 and December 31, 2020; 76,470,588 shares issued and 75,752,664 shares outstanding as of December 31, 2021, and 75,524,254 shares issued and 73,874,904 shares outstanding as of December 31, 2020	8	8
Additional paid-in capital	932,944	897,607
Accumulated deficit	(811,534)	(577,530)
Accumulated other comprehensive income	45	599
Total stockholders' equity	121,463	320,684
Total liabilities and stockholders' equity	$ 343,657	$ 539,433