Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 82,073	$ 79,790
Marketable investments (Note 3)	54,258	54,333
Accounts receivable, net	62,154	70,023
Deferred commissions	14,722	13,731
Prepaid expenses and other current assets	18,641	18,942
Total current assets	231,848	236,819
Property and equipment, net	24,487	25,249
Goodwill	76,900	76,169
Intangible assets, net	559	732
Other assets	6,942	6,231
Total assets	340,736	345,200
Current Liabilities:
Accounts payable	353	217
Accrued expenses and other current liabilities	35,260	49,629
Deferred revenue	155,425	145,207
Total current liabilities	191,038	195,053
Non-current liabilities	8,403	8,958
Total liabilities	199,441	204,011
Stockholders' Equity (Note 8):
Preferred stock, $0.01 par value Authorized - 500 shares; issued and outstanding - none
Common stock, $0.01 par value Authorized - 125,000 shares Issued - 22,514 and 22,432 shares as of March 31, 2018 and December 31, 2017, respectively Outstanding - 18,017 and 18,041 shares as of March 31, 2018 and December 31, 2017, respectively	225	224
Additional paid-in capital	186,335	181,910
Retained earnings	121,495	123,010
Treasury stock - 4,497 and 4,391 shares as of March 31, 2018 and December 31, 2017, respectively, at cost	(166,310)	(161,943)
Accumulated other comprehensive loss	(450)	(2,012)
Total stockholders’ equity	141,295	141,189
Total liabilities and stockholders’ equity	$ 340,736	$ 345,200