Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 59,614	$ 31,530
Marketable securities, current	136,509	137,522
Prepaid expenses and other current assets	4,122	2,738
Total current assets	200,245	171,790
Property and equipment, net	12,244	10,283
Deposits and other non-current assets	1,314	1,304
Marketable securities, non-current	860	1,100
Total assets	214,663	184,477
Current liabilities:
Accounts payable	1,558	1,020
Accrued expenses	7,697	11,497
Deferred revenue, current portion	19,840	3,380
Total current liabilities	29,095	15,897
Deferred rent	5,282	5,337
Deferred revenue, net of current portion	97,308	28,180
Other non-current liabilities	1,006	1,012
Total liabilities	132,691	50,426
Stockholders’ equity:
Common stock, $0.001 par value: 120,000,000 shares authorized at June 30, 2018 and December 31, 2017; 32,063,948 and 31,572,044 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	32	32
Additional paid-in capital	308,296	295,019
Accumulated other comprehensive loss	(125)	(287)
Accumulated deficit	(226,231)	(160,713)
Total stockholders’ equity	81,972	134,051
Total liabilities and stockholders’ equity	$ 214,663	$ 184,477