Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 31,063	$ 88,609
Short-term investments	39,950	3,503
Prepaid expenses and other current assets	848	1,211
Total current assets	71,861	93,323
Property and equipment, net	1,945	1,579
Restricted cash	122	122
Other assets	24	24
Total assets	73,952	95,048
Current liabilities:
Accounts payable	1,177	934
Accrued expenses	4,769	3,957
Current portion of deferred rent	1	4
Current portion of deferred revenue	2,105	2,105
Long-term debt, current portion		8,187
Total current liabilities	8,052	15,187
Deferred rent	821	101
Deferred revenue	1,776	2,829
Accrued expenses	1,414	1,276
Long-term debt, net of current portion	6,676	2,501
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized shares—5,000,000 at June 30, 2017 and December 31, 2016; 2,819,549 Class A Convertible Preferred shares issued and outstanding at June 30, 2017 and December 31, 2016	3	3
Common stock, $0.001 par value; authorized shares—150,000,000 at June 30, 2017 and December 31, 2016; issued and outstanding—41,415,796 at June 30, 2017 and 41,386,506 at December 31, 2016	41	41
Additional paid-in capital	250,825	248,957
Accumulated other comprehensive loss	(39)	(1)
Accumulated deficit	(195,617)	(175,846)
Total stockholders’ equity	55,213	73,154
Total liabilities and stockholders’ equity	$ 73,952	$ 95,048