Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 28,636	$ 28,810
Short-term investments	59,385	89,569
Prepaids and other current assets	3,066	2,481
Total current assets	91,087	120,860
Operating lease, right-of-use asset	13,246	13,849
Property and equipment, net	513	605
Other assets	75
Restricted cash	828	828
Total assets	105,749	136,142
Current liabilities:
Accounts payable	3,160	1,884
Accrued expenses	6,863	5,661
Operating lease liabilities	1,104	1,056
Total current liabilities	11,127	8,601
Derivative liability	3	3
Operating lease liabilities, net of current portion	12,634	13,196
Total liabilities	23,764	21,800
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of June 30, 2019 and December 31, 2018
Common stock, $0.001 par value; 125,000,000 shares authorized; 51,099,307 and 50,808,422 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	51	51
Additional paid-in capital	393,872	391,825
Accumulated other comprehensive income	33	1
Accumulated deficit	(311,971)	(277,535)
Total stockholders’ equity	81,985	114,342
Total liabilities and stockholders’ equity	$ 105,749	$ 136,142