Summary of Significant Accounting Policies - Effect of Changes in Balance Sheet Due to Adoption of New Revenue Standard (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 30, 2018	Dec. 29, 2018	Dec. 31, 2017	Dec. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets	$ 1,504		$ 2,528
Total current assets	91,517		95,633
Operating lease right-of-use assets	10,279	$ 11,635
Total assets	126,322		122,070
Current operating lease liabilities	2,524	2,581
Accounts payable	4,199		6,053
Other accrued liabilities	3,593		4,952		$ 7,688
Total current liabilities	20,811		30,008
Noncurrent operating lease liabilities	9,532	11,120
Other long-term liabilities	186		2,438
Total non-current liabilities	9,718		2,438
Total liabilities and stockholders' equity	126,322		122,070
Accumulated deficit	$ (63,786)		(64,934)		$ (66,881)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets		2,307
Total current assets		95,412
Operating lease right-of-use assets		11,635
Total assets		133,484
Current operating lease liabilities		2,581
Accounts payable		6,049
Other accrued liabilities		4,939
Total current liabilities		32,572
Noncurrent operating lease liabilities		11,120
Other long-term liabilities		168
Total non-current liabilities		11,288
Total liabilities and stockholders' equity		133,484
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other accrued liabilities				$ 9,322
Accumulated deficit				(68,515)
Accounting Standards Update 2014-09 | Difference Between Revenue Guidance in Effect Before and After Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other accrued liabilities				1,634
Accumulated deficit				$ (1,634)
Previously Reported | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets			2,528
Total current assets			95,633
Total assets			122,070
Accounts payable			6,053
Other accrued liabilities			4,952
Total current liabilities			30,008
Other long-term liabilities			2,438
Total non-current liabilities			2,438
Total liabilities and stockholders' equity			$ 122,070
Restatement Adjustment | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets		(221)
Total current assets		(221)
Operating lease right-of-use assets		11,635
Total assets		11,414
Current operating lease liabilities		2,581
Accounts payable		(4)
Other accrued liabilities		(13)
Total current liabilities		2,564
Noncurrent operating lease liabilities		11,120
Other long-term liabilities		(2,270)
Total non-current liabilities		8,850
Total liabilities and stockholders' equity		$ 11,414