Stockholders' Equity - Balance Sheet and Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Dec. 28, 2019
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	$ 10,225	$ 7,923
Cost of revenue – amortization from balance sheet	1,478	790
Total stock-based compensation expense	11,703	8,713
Cost of revenue
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	624	538
Research and development
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	3,774	3,603
Sales and marketing
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	2,644	1,547
General and administration
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects included in net loss before income taxes	3,183	$ 2,235
Stock-based compensation effects in inventory
Effects Of Stock Based Compensation [Line Items]
Stock-based compensation effects in inventory	$ 4,506		$ 4,798