CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 79,262	$ 54,043
Short-term investments	11,249	36,184
Accounts receivable, net of allowance for doubtful accounts of $433 at March 31, 2017 and December 31, 2016	38,073	43,755
Prepaid expenses and other current assets	13,016	6,131
TOTAL CURRENT ASSETS	141,600	140,113
Property and equipment-net	5,189	5,503
Intangible assets-net	490	645
Goodwill	5,475	5,475
Other assets	1,604	1,370
TOTAL ASSETS	154,358	153,106
Current liabilities:
Accounts payable	2,556	701
Accrued expenses	17,707	21,674
Deferred revenue-current	69,942	68,153
TOTAL CURRENT LIABILITIES	90,205	90,528
Long-term liabilities:
Deferred revenue-noncurrent	21,220	19,923
Other long-term liabilities	1,822	1,838
TOTAL LIABILITIES	113,247	112,289
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.0001 par value, 300,000,000 shares authorized, 92,180,440 shares and 89,066,031 shares issued and outstanding at March 31, 2017 and December 31, 2016,	9	9
Additional paid-in capital	396,320	383,193
Accumulated deficit	(355,218)	(342,385)
TOTAL STOCKHOLDERS' EQUITY	41,111	40,817
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 154,358	$ 153,106