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Stock-Based Compensation - Schedule of Employee Stock Purchase Plan (Details) - ESPP
3 Months Ended
Mar. 31, 2019
Apr. 01, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (months) 6 months 6 months
Risk-free interest rate 2.37% 1.39%
Volatility 53.77% 54.87%
Dividend yield 0.00% 0.00%