Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 125,390	$ 187,335
Available for sale securities	195,825	73,008
Unbilled receivable		33,823
Prepaid expenses and other current assets	11,174	2,155
Total current assets	332,389	296,321
Property and equipment, net	2,934	2,612
Other assets	1,499	1,283
Total assets	336,822	300,216
Current liabilities:
Accounts payable	10,212	2,039
Accrued expenses	28,851	30,261
Short-term deferred revenue	142,346	81,968
Short-term deferred rent	182
Total current liabilities	181,591	114,268
Deferred rent, net of current portion	2,678	2,480
Deferred revenue, net of current portion	95,531	115,321
Other non-current liabilities	24	27
Total liabilities	279,824	232,096
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock $0.00001 par value, 25,000,000 shares authorized at June 30, 2017 and December 31, 2016; 0 shares issued and outstanding at June 30, 2017 and December 31, 2016
Common stock: $0.00001 par value; 175,000,000 shares authorized at June 30, 2017 and December 31, 2016; 42,490,957 and 38,615,709 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	420,448	365,298
Accumulated other comprehensive loss	(254)	(42)
Accumulated deficit	(363,196)	(297,136)
Total stockholders' equity	56,998	68,120
Total liabilities and stockholders' equity	$ 336,822	$ 300,216