Unaudited Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 37,865	$ 46,985
Short-term investments	12,472	0
Prepaid expenses and other current assets	2,401	1,452
Total current assets	52,738	48,437
Other assets	426	419
Deferred offering costs	360	417
Total assets	53,524	49,273
Current liabilities:
Accounts payable	1,136	619
Accrued expenses	2,910	3,149
Accrued severance and retention costs	220	2,639
Deferred revenue, current portion	257	257
Total current liabilities	4,523	6,664
Deferred revenue, non-current	507	635
Deferred rent	25	25
Warrant liability	4,594	0
Total liabilities	9,649	7,324
Commitments and contingencies
Stockholders’ equity:
Preferred stock	0	0
Common stock	23	14
Additional paid-in capital	209,298	192,069
Accumulated deficit	(165,446)	(150,134)
Total stockholders’ equity	43,875	41,949
Total liabilities and stockholders’ equity	$ 53,524	$ 49,273