| Stock-Based Compensation, Employee Benefit Plans and Convertible Preferred Stock - Stock-Based Compensation (Detail) (USD $) In Thousands, unless otherwise specified | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | |
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Stock-based compensation | $ 9,984 | $ 7,368 | $ 4,215 | 
| Cost of net revenue [Member] | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Stock-based compensation | 85 | 54 | 80 | 
| Research and development [Member] | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Stock-based compensation | 6,382 | 4,434 | 2,589 | 
| Selling, general and administrative [Member] | |||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | |||
| Stock-based compensation | $ 3,517 | $ 2,880 | $ 1,546 | 
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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