Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 53,148	$ 86,553
Short-term investments	18,779
Accounts receivables, net	49,154	44,164
Prepaid expenses and other current assets	9,152	6,148
Total current assets	130,233	136,865
Long-term investments	20,162
Property and equipment, net	8,088	7,532
Goodwill	75,110	74,565
Intangible assets, net	8,946	11,385
Other assets	764	214
Total assets	243,303	230,561
Current liabilities:
Accounts payable	4,012	2,038
Accrued expenses	23,499	24,707
Deferred revenue, current portion	116,903	87,917
Other current liabilities	1,195	1,105
Total current liabilities	145,609	115,767
Deferred revenue, non-current portion	52,160	42,400
Other long-term liabilities	3,496	4,319
Total liabilities	201,265	162,486
Stockholders' equity:
Preferred stock, $0.01 par value per share; 10,000,000 shares authorized at December 31, 2016 and 2015; 0 shares issued and outstanding at December 31, 2016 and 2015
Common stock, $0.01 par value; 100,000,000 shares authorized at December 31, 2016 and 2015; 43,018,737 and 41,942,026 shares issued at December 31, 2016 and 2015, respectively; 42,554,683 and 41,540,400 shares outstanding at December 31, 2016 and 2015, respectively	426	415
Treasury stock, at cost, 464,054 and 401,626 shares at December 31, 2016 and 2015, respectively	(4,391)	(3,526)
Additional paid-in-capital	435,360	411,524
Accumulated other comprehensive loss	(19)
Accumulated deficit	(389,338)	(340,338)
Total stockholders' equity	42,038	68,075
Total liabilities and stockholders' equity	$ 243,303	$ 230,561