BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 98,930	$ 90,943
Short-term investments	6,966	739
Prepaid expenses and other current assets	3,139	2,452
Total current assets	109,035	94,134
Property and equipment, net	2,105	2,265
Other assets	2,303	2,443
Total assets	113,443	98,842
Current liabilities:
Accounts payable	3,733	2,763
Accrued expenses	5,770	5,268
Total current liabilities	9,503	8,031
Other long-term liabilities	2,795	3,042
Total liabilities	12,298	11,073
Series A convertible preferred stock, $0.001 par value; 25,000,000 shares authorized, 9,303 shares issued and outstanding at June 30, 2020 and 30,000 issued and outstanding at December 31, 2019		28,200
Commitments and contingencies (Note 9)
Stockholders' equity:
Series A convertible preferred stock, $0.001 par value; 25,000,000 shares authorized, 9,303 shares issued and outstanding at June 30, 2020 and 30,000 issued and outstanding at December 31, 2019	8,745
Common stock, $0.001 par value; 300,000,000 shares authorized, 122,215,683 issued and 122,194,683 outstanding at June 30, 2020 and 86,500,353 issued and 86,471,122 outstanding at December 31, 2019	123	87
Additional paid-in capital	371,051	295,056
Treasury stock at cost, 29,231 shares at June 30, 2020 and December 31, 2019
Accumulated other comprehensive income	27
Accumulated deficit	(278,801)	(235,574)
Total stockholders' equity	101,145	59,569
Total liabilities and stockholders' equity	$ 113,443	$ 98,842