CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 4,405	$ 25,222
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	7,935	10,646
Provision for doubtful accounts receivable, product returns, and inventory valuation	795	2,896
Stock compensation expense	3,945	4,054
Income tax benefits relating to employee stock options	(314)
Deferred taxes	8,202	9,297
Other	322	486
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in business combinations:
Change in operating assets	13,008	(4,128)
Change in operating liabilities	7,197	(81,412)
Net cash provided by (used in) operating activities	45,495	(32,939)
Cash flows from investing activities:
Purchases of property and equipment	(9,840)	(5,289)
Payments for business combinations		(1,297)
Payments for intangible asset acquisition	(7,000)
Net cash used in investing activities	(16,840)	(6,586)
Cash flows from financing activities:
Proceeds from exercise of stock options and issuance of common stock	3,688	1,606
Income tax benefits relating to employee stock options	314
Net cash provided by financing activities	4,002	1,606
Effect of exchange rate changes on cash and cash equivalents	(408)	(440)
Net increase (decrease) in cash and cash equivalents	32,249	(38,359)
Cash and cash equivalents, beginning of period	218,787	219,605
Cash and cash equivalents, end of period	$ 251,036	$ 181,246