Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 140,371	$ 31,530
Marketable securities, current	77,827	137,522
Prepaid expenses and other current assets	2,433	2,738
Total current assets	220,631	171,790
Property and equipment, net	11,458	10,283
Deposits and other non-current assets	1,617	1,304
Marketable securities, non-current	1,320	1,100
Total assets	235,026	184,477
Current liabilities:
Accounts payable	1,372	1,020
Accrued expenses	9,351	11,497
Deferred revenue, current	20,217	3,380
Total current liabilities	30,940	15,897
Deferred rent	5,279	5,337
Deferred revenue, non-current	99,506	28,180
Other non-current liabilities	1,008	1,012
Total liabilities	136,733	50,426
Commitments and contingencies (see note 6)
Stockholders’ equity:
Preferred stock $0.001 par value: 5,000,000 shares authorized at March 31, 2018 and December 31, 2017; no shares issued and outstanding at March 31, 2018 and December 31, 2017
Common stock, $0.001 par value: 120,000,000 shares authorized at March 31, 2018 and December 31, 2017; 31,888,998 and 31,572,044 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	32	32
Additional paid-in capital	299,112	295,019
Accumulated other comprehensive loss	(162)	(287)
Accumulated deficit	(200,689)	(160,713)
Total stockholders’ equity	98,293	134,051
Total liabilities and stockholders’ equity	$ 235,026	$ 184,477