CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 147,888	$ 127,683
Short-term investments	385,422	445,315
Accounts receivable (net of allowances of $2,820 and $3,782 at March 31, 2017 and December 31, 2016, respectively)	101,640	85,591
Prepaid expenses and other current assets	12,987	12,100
Income tax receivable	12,704	15,165
Total current assets	660,641	685,854
Non-current assets:
Property, equipment and capitalized software, net	78,826	76,420
Goodwill	184,557	184,557
Intangible assets, net	99,776	103,549
Other assets	3,854	2,964
Total assets	1,027,654	1,053,344
Current liabilities:
Accounts payable	17,672	16,474
Accrued compensation	10,072	15,211
Other current liabilities	14,443	9,468
Deferred revenue	16,851	11,850
Deferred rent	1,065	1,016
Credit facilities	33,750	30,000
Capital lease obligation	117	115
Total current liabilities	93,970	84,134
Non-current liabilities:
Credit facilities, less current portion	225,000	236,250
Capital lease obligation, less current portion	187	215
Deferred rent	1,194	1,457
Other liabilities	7,403	13,158
Deferred income taxes	34,497	34,553
Total liabilities	362,251	369,767
Commitments and contingencies (Note 5)
Stockholders' equity:
Common stock
Preferred stock, $0.0001 par value, 100,000,000 shares authorized, zero shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively
Additional paid-in-capital	519,691	516,300
Retained earnings	277,729	274,087
Other comprehensive income (loss)	(404)	(580)
Total stockholders' equity	665,403	683,577
Total liabilities and stockholders' equity	1,027,654	1,053,344
Class A Common
Stockholders' equity:
Common stock
Treasury stock, Class A common stock, at cost, 9,650,386 and 7,508,985 shares at March 31, 2017 and December 31, 2016, respectively	(131,614)	(106,231)
Class B Common
Stockholders' equity:
Common stock	$ 1	$ 1