Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 28, 2019	Jun. 29, 2019	Sep. 29, 2018	Jun. 30, 2018	Sep. 28, 2019	Sep. 29, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, common stock, shares		9,098,320			9,098,320
Ending balance, common stock, shares	9,127,466				9,127,466
Beginning balance	$ 550,337	$ 529,588	$ 475,687	$ 457,106	$ 529,588	$ 457,106
Net income	20,885	21,282	15,576	19,691	42,167	35,267
Issuance of common stock under stock incentive plans	941	(1,252)	1,995	(2,168)
Stock-based compensation	818	630	1,516	599
Other comprehensive income, net	23	89	(26)	5
Ending balance	$ 573,004	$ 550,337	$ 494,748	$ 475,687	$ 573,004	$ 494,748
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, common stock, shares	9,111,624	9,098,320	9,061,306	9,044,858	9,098,320	9,044,858
Issuance of common stock under stock incentive plans, shares	15,842	13,304	36,053	16,448
Ending balance, common stock, shares	9,127,466	9,111,624	9,097,359	9,061,306	9,127,466	9,097,359
Beginning balance	$ 91	$ 91	$ 91	$ 90	$ 91	$ 90
Net income	0	0	0	0
Issuance of common stock under stock incentive plans	0	0	0	1
Stock-based compensation	0	0	0	0
Other comprehensive income, net	0	0	0	0
Ending balance	91	91	91	91	91	91
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	248,825	249,447	244,627	246,197	249,447	246,197
Net income	0	0	0	0
Issuance of common stock under stock incentive plans	941	(1,252)	1,995	(2,169)
Stock-based compensation	818	630	1,516	599
Other comprehensive income, net	0	0	0	0
Ending balance	250,584	248,825	248,138	244,627	250,584	248,138
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	301,360	280,078	231,147	209,381	280,078	209,381
Net income	20,885	21,282	15,576	19,691
Issuance of common stock under stock incentive plans	0	0	0	0
Stock-based compensation	0	0	0	0
Other comprehensive income, net	0	0	0	0
Ending balance	322,245	301,360	246,723	231,147	322,245	246,723
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	61	(28)	(178)	1,438	(28)	1,438
Net income	0	0	0	0
Issuance of common stock under stock incentive plans	0	0	0	0
Stock-based compensation	0	0	0	0
Other comprehensive income, net	23	89	(26)	5
Ending balance	$ 84	$ 61	$ (204)	(178)	$ 84	$ (204)
ASU 2016-01, net
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0
ASU 2016-01, net | Common Stock
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0
ASU 2016-01, net | Additional paid-in capital
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0
ASU 2016-01, net | Retained earnings
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				1,621
ASU 2016-01, net | Accumulated other comprehensive income (loss)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				(1,621)
ASC 606, net
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				454
ASC 606, net | Common Stock
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0
ASC 606, net | Additional paid-in capital
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0
ASC 606, net | Retained earnings
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				454
ASC 606, net | Accumulated other comprehensive income (loss)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				$ 0