CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 30,415	$ 30,170	$ 24,153
Adjustment to net income for discontinued operation (income) loss	(184)	(1,839)	166
Net income from continuing operations	30,231	28,331	24,319
Adjustments to reconcile net income to net cash provided by operating activities from continuing operations:
Stock-based compensation	20,801	19,138	18,430
Excess tax benefit from stock-based compensation	(7,785)	(7,055)	(3,878)
Depreciation and amortization	25,879	22,632	17,610
Amortization of debt issuance costs	381	32
Provision for doubtful accounts	403	230	188
Provision for (reduction of) sales return reserves	1,154	(187)	(616)
Non-cash impairment loss		500
Deferred income taxes	5,230	4,700	8,423
Other	(252)	71	263
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	575	(10,198)	(5,619)
Prepaid and other assets	822	(6,977)	2,393
Accounts payable	(5,368)	3,734	1,997
Accrued liabilities	(2,055)	3,069	3,053
Deferred revenues	7,151	18,560	8,519
Income taxes payable	9,453	6,604	1,136
Net cash provided by operating activities from continuing operations	86,620	83,184	76,218
Cash flows from investing activities:
Cash used in acquisitions, net of cash acquired	(700)	(97,092)	(4,719)
Purchases of property and equipment	(6,369)	(11,252)	(17,418)
Capitalized software development costs	(2,137)	(2,358)	(2,144)
Purchases of marketable securities	(220,994)	(89,236)	(46,496)
Sales and maturities of marketable securities	118,588	87,428	36,496
Change in restricted cash	95
Net cash used in investing activities from continuing operations	(111,517)	(112,510)	(34,281)
Cash flows from financing activities:
Proceeds from exercises of stock options	5,173	7,189	14,020
Withholding taxes related to equity award net share settlement	(5,496)	(5,775)	(5,467)
Common stock repurchased and retired	(41,275)	(51,582)	(35,881)
Proceeds from common stock issued under the employee stock purchase plan	6,661	6,158	5,793
Proceeds from debt	50,000	50,000
Repayment of debt	(5,000)
Debt issuance costs		(1,901)
Excess tax benefits from stock-based compensation	7,785	7,055	3,878
Net cash provided by (used in) financing activities from continuing operations	17,848	11,144	(17,657)
Net cash transferred (to) from discontinued operation	(561)	1,655	(112)
Effect of exchange rate changes on cash and cash equivalents	302	104	(97)
Net change in cash and cash equivalents from continuing operations	(7,308)	(16,423)	24,071
Cash and cash equivalents of continuing operations at beginning of period	65,525	81,948	57,877
Cash and cash equivalents of continuing operations at end of period	58,217	65,525	81,948
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	2,988	2,533	1,687
Cash paid for interest	1,737
Cash flow from discontinued operation:
Net cash used in operating activities	(561)	(1,349)	(377)
Net cash provided by investing activities		3,004
Net cash transferred from (to) continuing operations	561	(1,655)	112
Effect of exchange rates on cash and cash equivalents			(1)
Net change in cash and cash equivalents from discontinued operation	0	0	(266)
Cash and cash equivalents of discontinued operation at beginning of period	0	0	266
Cash and cash equivalents of discontinued operation at end of period	$ 0	$ 0	$ 0