Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 270,936	$ 62,351
Short-term marketable securities	0	37,439
Prepaid expenses and other current assets	3,998	1,536
Total current assets	274,934	101,326
Property and equipment, net	1,698	2,164
Operating lease right-of-use assets	11,343	2,598
Other assets	2,153	1,453
Total assets	290,128	107,541
Current liabilities:
Accounts payable	4,528	7,296
Accrued expenses	11,173	8,986
Deferred revenue	3,998	4,815
Operating lease liabilities	1,280	2,219
Short-term debt	0	667
Other liabilities	91	87
Total current liabilities	21,070	24,070
Operating lease liabilities	10,606	677
Long-term debt, net	4,944	4,201
Other liabilities	200	275
Total liabilities	36,820	29,223
Commitments (Note 11)
Stockholders' equity:
Preferred stock, $0.0001 par value; 25,000,000 shares authorized; 0 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively	0	0
Common stock,$0.0001 par value; 175,000,000 shares authorized; 68,470,081 and 45,388,023 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively	7	5
Additional paid-in capital	504,876	270,662
Accumulated other comprehensive income (loss)	0	25
Accumulated deficit	(251,575)	(192,374)
Total stockholders’ equity	253,308	78,318
Total liabilities and stockholders’ equity	$ 290,128	$ 107,541