Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 32,912	$ 88,952
Accounts receivable	500
Short-term investments and related maturity receivables	55,722	11,997
Prepaid expenses and other current assets	1,491	1,647
Total current assets	90,625	102,596
Property and equipment, net	2,649	2,550
Restricted cash	122	122
Other assets	24	24
Total assets	93,420	105,292
Current liabilities:
Accounts payable	2,160	1,678
Accrued expenses	7,440	7,254
Current portion of deferred rent	125	12
Current portion of deferred revenue	2,105	2,105
Long-term debt, current portion	758
Total current liabilities	12,588	11,049
Deferred rent	1,303	1,347
Deferred revenue	198	724
Accrued expenses	267	175
Long-term debt, net of current portion	14,069	14,808
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized shares—5,000,000 at March 31, 2018 and December 31, 2017; 2,819,549 Class A Convertible Preferred shares issued and outstanding at March 31, 2018 and December 31, 2017	3	3
Common stock, $0.001 par value; authorized shares—150,000,000 at March 31, 2018 and December 31, 2017; issued and outstanding—52,857,734 at March 31, 2018 and 52,648,601 at December 31, 2017	53	53
Additional paid-in capital	297,885	295,934
Accumulated other comprehensive loss	(13)	(3)
Accumulated deficit	(232,933)	(218,798)
Total stockholders’ equity	64,995	77,189
Total liabilities and stockholders’ equity	$ 93,420	$ 105,292