Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
CURRENT ASSETS
Cash and cash equivalents	$ 80,231	$ 90,095
Marketable securities	46,429	56,178
Accounts receivable - license	21,500
Prepaid expenses and other current assets	3,252	3,516
Total current assets	151,412	149,789
Restricted cash	1,845	1,842
Property and equipment, net	5,518	5,642
Operating lease right-of-use assets	4,123	4,230
Other non-current assets	716	115
TOTAL ASSETS	163,614	161,618
CURRENT LIABILITIES
Accounts payable	1,878	2,254
Operating lease liabilities	315	319
Deferred revenue	19,226
Accrued and other current liabilities	10,951	13,870
Total current liabilities	32,370	16,443
Non-current operating lease liabilities	5,009	5,129
Deferred revenue, net of current portion	2,274
Other non-current liabilities	206	214
TOTAL LIABILITIES	39,859	21,786
Commitments and Contingencies (Note 8)
STOCKHOLDERS’ EQUITY
Preferred stock, $0.0001 par value; 10,000,000 shares authorized as of March 31, 2021 and December 31, 2020; no shares issued and outstanding as of March 31, 2021 and December 31, 2020
Common stock, $0.0001 par value; 500,000,000 shares authorized as of March 31, 2021 and December 31, 2020; 49,019,901 shares and 47,959,086 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively	5	5
Additional paid-in capital	417,951	415,824
Accumulated other comprehensive income	25	11
Accumulated deficit	(294,226)	(276,008)
TOTAL STOCKHOLDERS’ EQUITY	123,755	139,832
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 163,614	$ 161,618