Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 87,250	$ 187,335
Available for sale securities	164,555	73,008
Unbilled receivable		33,823
Prepaid expenses and other current assets	3,248	2,155
Total current assets	255,053	296,321
Property and equipment, net	2,904	2,612
Other assets	1,299	1,283
Total assets	259,256	300,216
Current liabilities:
Accounts payable	15,083	2,039
Accrued expenses	34,272	30,261
Short-term deferred revenue	84,108	81,968
Total current liabilities	133,463	114,268
Deferred rent	2,835	2,480
Deferred revenue, net of current portion	92,315	115,321
Other non-current liabilities	26	27
Total liabilities	228,639	232,096
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock $0.00001 par value, 25,000,000 shares authorized at March 31, 2017 and December 31, 2016; 0 shares issued and outstanding at March 31, 2017 and December 31, 2016
Common stock: $0.00001 par value; 175,000,000 shares authorized at March 31, 2017 and December 31, 2016; 38,829,562 and 38,615,709 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	372,475	365,298
Accumulated other comprehensive loss	(179)	(42)
Accumulated deficit	(341,679)	(297,136)
Total stockholders' equity	30,617	68,120
Total liabilities and stockholders' equity	$ 259,256	$ 300,216