Income Taxes - Components of Company's Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Net operating loss carry forwards	$ 45,391	$ 9,483
Research credits	1,155	7,766
Stock based compensation	2,896	5,333
Deferred revenue	4,596	9,329
Development costs	5,298
Depreciation and amortization differences		13,437
Returns and Allowances	7,889	1,877
Other, net	6,021	91
Total deferred tax assets before valuation allowance	73,246	47,316
Valuation allowance	(22,819)	(47,316)
Total deferred tax assets	50,427
Deferred tax liabilities:
Depreciation and amortization differences	(37,130)
Net deferred tax	$ 13,297