Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 79,790	$ 76,958
Marketable investments (Note 3)	54,333	61,147
Accounts receivable, net (Note 11)	70,023	58,812
Deferred commissions	13,731	12,052
Prepaid expenses and other current assets	18,942	14,467
Total current assets	236,819	223,436
Property and equipment, net (Note 11)	25,249	23,894
Goodwill (Note 2)	76,169	73,193
Intangible assets, net (Note 2)	732	1,464
Other assets	6,231	13,798
Total assets	345,200	335,785
Current Liabilities:
Accounts payable	217	1,806
Accrued expenses and other current liabilities (Note 11)	49,629	41,403
Deferred revenue	145,207	134,265
Total current liabilities	195,053	177,474
Non-current liabilities	8,958	8,275
Total liabilities	204,011	185,749
Commitments (Note 6)
Stockholders' Equity (Note 7):
Preferred stock, $0.01 par value Authorized - 500 shares, issued and outstanding - none
Common stock, $0.01 par value Authorized - 125,000 shares Issued - 22,432 and 21,719 shares as of December 31, 2017 and 2016, respectively Outstanding - 18,041 and 18,361 shares as of December 31, 2017 and 2016, respectively	224	217
Additional paid-in capital	181,910	157,569
Retained earnings	123,010	121,799
Treasury stock - 4,391 and 3,358 shares as of December 31, 2017 and 2016, respectively, at cost	(161,943)	(121,976)
Accumulated other comprehensive loss	(2,012)	(7,573)
Total stockholders’ equity	141,189	150,036
Total liabilities and stockholders’ equity	$ 345,200	$ 335,785