Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 32,354	$ 26,591
Short-term marketable securities	75,605	88,143
Accounts receivable	288	784
Prepaid expenses and other current assets	3,111	2,025
Total current assets	111,358	117,543
Property and equipment, net	2,593	2,319
Long-term marketable securities		10,482
Other assets	1,804	371
Total assets	115,755	130,715
Current liabilities:
Accounts payable	2,522	3,070
Accrued expenses	5,912	6,944
Deferred rent		232
Deferred revenue	20,903	21,635
Total current liabilities	29,337	31,881
Deferred rent, net of current portion	312	67
Deferred revenue, net of current portion	29,559	28,773
Commitments (Note 10)
Stockholder's equity (deficit)
Preferred stock, $0.0001 par value; 25,000,000 shares authorized; 0 shares issued and outstanding at March 31, 2018
Common stock, $0.0001 par value; 175,000,000 shares authorized; 22,869,962 and 22,765,017 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	3	3
Additional paid-in capital	169,018	168,018
Accumulated other comprehensive loss	(162)	(149)
Accumulated deficit	(112,312)	(97,878)
Total stockholders’ equity	56,547	69,994
Total liabilities and stockholders’ equity	$ 115,755	$ 130,715