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Equity Incentive Plans and Stock-Based Compensation - Summary of Activity under Stock Option Plans (Details) - USD ($)
$ / shares in Units, $ in Thousands
 9 Months Ended
Sep. 30, 2017
Sep. 29, 2017
Number of Shares (thousands)    
Outstanding options, Beginning balance (in shares) 7,868,000  
Granted (in shares) 135,000  
Exercised (in shares) (1,272,000)  
Canceled (in shares) (421,000)  
Outstanding options, Ending balance (in shares) 6,310,000  
Vested and exercisable (in shares) 5,152,000  
Weighted-Average Exercise Price    
Beginning balance (in dollars per share) $ 4.82  
Granted (in dollars per share) 8.42  
Exercised (in dollars per share) 3.35  
Canceled (in dollars per share) 6.40  
Ending balance (in dollars per share) 5.09  
Vested and exercisable at end of period (in dollars per share) $ 5.01  
Weighted-average remaining contractual term (in years) 5 years 6 months  
Weighted average remaining contractual term, Vested and exercisable at end of period (in years) 4 years 10 months 24 days  
Aggregate Intrinsic Value $ 17,668  
Aggregate Intrinsic Value, Vested and exercisable at end of period $ 15,004  
Number of shares available for future grant 112,431  
Closing price (in dollars per share)   $ 7.56