Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 28, 2019	Dec. 29, 2018
Income Taxes [Line Items]
Income tax benefits	$ 0	$ 0
Operating loss carryforwards, limitations on use	These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income or tax liabilities. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period.
Valuation allowance	$ 101,029,000	95,024,000	$ 85,316,000
Increase in valuation allowance	6,000,000
Unrecognized tax benefits	0	0
Unrecognized tax benefits, related interest and penalties accrued	0	0
Accrued interest or penalties related to uncertain tax positions	0	0
U.S. Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 322,000,000
Operating loss carryforwards begin to expire	2021
U.S. Federal [Member] | Non-expirable [member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 108,000,000
U.S. Federal [Member] | Research and Development Credit Carry Forwards [Member]
Income Taxes [Line Items]
Tax credit carryforwards	$ 7,600,000
Tax credits carryforwards begin to expire	2021
State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 252,700,000
Operating loss carryforwards begin to expire	2030
State [Member] | Research and Development Credit Carry Forwards [Member]
Income Taxes [Line Items]
Tax credit carryforwards	$ 5,000,000
Tax credits carryforwards begin to expire	2024
Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 0
Maximum [Member]
Income Taxes [Line Items]
Foreign income tax provision	$ 100,000	$ 100,000
Minimum [Member]
Income Taxes [Line Items]
Percentage of change in ownership for operating loss carryforward	50.00%
Period for change in ownership percentage	3 years
Open Tax Year	2017