Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 178,674	$ 294,233
Marketable securities	1,446,567	1,448,063
Prepaid expenses and other current assets	37,206	39,841
Collaboration receivable - related party	19,797	18,506
Total current assets	1,682,244	1,800,643
Property and equipment, net	2,840	3,016
Restricted cash	1,269	1,269
Right-of-use operating asset	14,759	16,109
Other long-term assets	4,591	4,251
Total assets	1,705,703	1,825,288
Current liabilities:
Accounts payable	7,129	10,450
Accrued expenses	63,051	67,275
Operating lease liability, current portion	7,523	7,468
Total current liabilities	77,703	85,193
Operating lease liability, net of current portion	9,396	10,964
Other liabilities	102	100
Total liabilities	87,201	96,257
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at March 31, 2022 and December 31, 2021; no shares issued or outstanding at March 31, 2022 and December 31, 2021
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at March 31, 2022 and December 31, 2021; 59,069,182 and 58,940,083 shares issued at March 31, 2022 and December 31, 2021; 59,066,149 and 58,937,050 shares outstanding at March 31, 2022 and December 31, 2021	6	6
Treasury stock, at cost, 3,033 shares at March 31, 2022 and December 31, 2021	(400)	(400)
Additional paid-in capital	3,247,538	3,227,471
Accumulated deficit	(1,617,441)	(1,495,386)
Accumulated other comprehensive loss	(11,201)	(2,660)
Total stockholders’ equity	1,618,502	1,729,031
Total liabilities and stockholders’ equity	$ 1,705,703	$ 1,825,288