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Stock-Based Compensation - Valuation Assumptions Used to Estimate Grant-Date Fair Value (Details)
3 Months Ended 9 Months Ended
Sep. 27, 2019
Sep. 28, 2018
Sep. 27, 2019
Sep. 28, 2018
Stock options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Risk-free interest rate 1.57% 2.91% 1.82% 2.83%
Dividend yield 0.00% 0.00% 0.00% 0.00%
Expected volatility 48.00% 55.00% 48.00% 55.00%
Expected life 4 years 4 years 4 months 24 days 4 years 4 months 24 days 4 years 4 months 24 days
ESPP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Risk-free interest rate 2.09% 2.11% 2.34% 1.74%
Dividend yield 0.00% 0.00% 0.00% 0.00%
Expected volatility 43.00% 51.00% 52.00% 52.00%
Expected life 6 months 6 months 6 months 6 months