Condensed Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 50,363	$ 66,373
Available for sale securities	109,519	143,674
Prepaid expenses and other current assets	3,806	4,791
Income tax receivable	0	1,765
Total current assets	163,688	216,603
Property and equipment, net	8	26
Right-of-use asset, net	1,971	120
Other assets	0	5
Total assets	165,667	216,754
Current liabilities
Accrued research and development expenses	15,412	12,284
Accounts payable and accrued expenses	8,643	12,792
Lease liability	937	54
Total current liabilities	24,992	25,130
Lease liability, non-current	1,102	61
Total liabilities	26,094	25,191
Stockholders' equity
Preferred stock—$0.001 par value, 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock—$0.001 par value, 200,000,000 shares authorized, 90,386,770 and 90,120,797 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	90	90
Additional paid-in capital	761,491	756,543
Accumulated deficit	(622,011)	(565,073)
Accumulated other comprehensive income	3	3
Total stockholders' equity	139,573	191,563
Total liabilities and stockholders' equity	$ 165,667	$ 216,754