Income Taxes Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Net operating loss and capital loss carryforwards	$ 37,183	$ 36,661
Credit carryforwards	8,806	8,075
Reserves and accruals	19,703	18,236
Translation gains	43	33
Stock-based compensation	9,908	9,490
Total deferred tax assets, gross	75,643	72,495
Deferred tax liabilities:
Prepaid expenses	345	560
Depreciation and amortization	9,903	12,776
Total deferred tax liabilities, gross	10,248	13,336
Net deferred tax assets before valuation allowance	65,395	59,159
Valuation allowance	(27,056)	(20,224)
Net deferred tax assets	$ 38,339	$ 38,935