Effect of Changes in Balance Sheet Due to Adoption of New Revenue Standard (Detail) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 30, 2018	Dec. 29, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets	$ 2,173		$ 2,528
Total current assets	87,799		95,633
Operating lease right-of-use assets	11,076	$ 11,635
Total assets	125,293		122,070
Current operating lease liabilities	2,569	2,581
Accounts payable	4,867		6,053
Other accrued liabilities	4,327		4,952
Total current liabilities	25,555		30,008
Noncurrent operating lease liabilities	10,491	11,120
Other long-term liabilities	160		2,438
Total non-current liabilities	10,651		2,438
Total liabilities and stockholders' equity	$ 125,293		122,070
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
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
Operating lease right-of-use assets
Total assets			122,070
Current operating lease liabilities
Accounts payable			6,053
Other accrued liabilities			4,952
Total current liabilities			30,008
Noncurrent operating lease liabilities
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