Income Taxes - Textual (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
U.S. federal income tax rate, percent	21.00%	21.00%	21.00%
Deferred tax assets, valuation allowance	$ 14,238	$ 14,160
Maximum amount company recognize from unrecognized tax benefit	13,486	15,143	$ 5,528	$ 4,880
Unrecognized tax benefits that would reflect as adjustment to income tax expense if recognized	8,863	10,649
Unrecognized tax benefits, income tax penalties and interest expense	(193)	236		$ 199
Unrecognized tax benefits, income tax penalties and interest accrued	1,487	$ 1,681
California [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	7,824
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2,873
Research and development tax credit carryforward	$ 3,150
Foreign [Member] | Research and Development Credit [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward expiration date	Dec. 31, 2029
Foreign [Member] | Switzerland [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	$ 2,797
Foreign [Member] | United Kingdom [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	467
Federal [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	3,150
Operating loss carryforwards	85
Research and development tax credit carryforward	5,731
State [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,892
Research and development tax credit carryforward	$ 10,664