CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 135,394	$ 106,174
Short-term investments	34,582	69,172
Accounts receivable, net of allowance for doubtful accounts of $1,035 and $1,338 at June 30, 2017 and December 31, 2016, respectively	74,552	71,945
Prepaid expenses and other current assets	8,527	6,293
Total current assets	253,055	253,584
Property and equipment, net	15,655	16,376
Intangible assets, net	52,401	47,987
Goodwill	80,506	43,895
Other assets	892	914
Total assets	402,509	362,756
Current liabilities:
Accounts payable	4,110	4,968
Accrued compensation and benefits	10,807	13,202
Other current liabilities	22,383	20,864
Deferred revenues	7,975	6,856
Total current liabilities	45,275	45,890
Other non-current liabilities	589	78
Deferred rent	2,062	2,285
Contingent consideration related to acquisitions	14,800	185
Deferred tax liabilities	2,497	2,569
Total liabilities	65,223	51,007
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, $0.00001 par value—10,000,000 shares authorized and no shares issued or outstanding at June 30, 2017 and December 31, 2016
Common stock, $0.00001 par value—250,000,000 shares authorized; 101,840,994 shares issued and 92,193,287 outstanding at June 30, 2017; 98,208,117 shares issued and 88,560,409 outstanding at December 31, 2016	1	1
Additional paid-in capital	684,776	647,474
Treasury stock, at cost	(96,574)	(96,574)
Accumulated other comprehensive loss	(700)	(748)
Accumulated deficit	(250,217)	(238,404)
Total stockholders’ equity	337,286	311,749
Total liabilities and stockholders’ equity	$ 402,509	$ 362,756