Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 50,662	$ 53,148
Short-term investments	28,561	18,779
Accounts receivable, net of allowance for doubtful accounts of $1,130 and $1,061 at March 31, 2017 and December 31, 2016, respectively	33,703	49,154
Prepaid expenses and other current assets	7,742	9,152
Total current assets	120,668	130,233
Long-term investments	16,803	20,162
Property and equipment, net	8,010	8,088
Goodwill	75,110	75,110
Intangible assets, net	8,460	8,946
Other assets	720	764
Total assets	229,771	243,303
Current liabilities:
Accounts payable	3,495	4,012
Accrued expenses	16,346	23,499
Deferred revenue, current portion	116,564	116,903
Other current liabilities	1,239	1,195
Total current liabilities	137,644	145,609
Deferred revenue, non-current portion	51,083	52,160
Other long-term liabilities	3,187	3,496
Total liabilities	191,914	201,265
Stockholders’ equity:
Preferred stock, $0.01 par value per share; 10,000,000 shares authorized at March 31, 2017 and December 31, 2016; 0 shares issued at March 31, 2017 and December 31, 2016	0	0
Common stock, $0.01 par value per share; 100,000,000 shares authorized at March 31, 2017 and December 31, 2016; 43,309,925 and 43,018,737 shares issued at March 31, 2017 and December 31, 2016, respectively; 42,840,896 and 42,554,683 shares outstanding at March 31, 2017 and December 31, 2016, respectively	428	426
Treasury stock, at cost, 469,029 and 464,054 shares at March 31, 2017 and December 31, 2016, respectively	(4,457)	(4,391)
Additional paid-in-capital	441,913	435,360
Accumulated other comprehensive loss	(39)	(19)
Accumulated deficit	(399,988)	(389,338)
Total stockholders’ equity	37,857	42,038
Total liabilities and stockholders’ equity	$ 229,771	$ 243,303