Unaudited Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 38,016	$ 46,985
Prepaid expenses and other current assets	1,905	1,452
Total current assets	39,921	48,437
Other assets	429	419
Deferred offering costs	331	417
Total assets	40,681	49,273
Current liabilities:
Accounts payable	1,380	619
Accrued expenses	2,574	3,149
Accrued severance and retention costs, current portion	830	2,639
Deferred revenue, current portion	257	257
Total current liabilities	5,041	6,664
Deferred revenue, non-current	571	635
Deferred rent	25	25
Total liabilities	$ 5,637	$ 7,324
Commitments and contingencies
Stockholders’ equity:
Preferred stock	$ 0	$ 0
Common stock	14	14
Additional paid-in capital	192,348	192,069
Accumulated deficit	(157,318)	(150,134)
Total stockholders’ equity	35,044	41,949
Total liabilities and stockholders’ equity	$ 40,681	$ 49,273