Stock-Based Compensation - Summary of Stock Option Activity (Detail)	9 Months Ended
	Sep. 29, 2018 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Shares | shares	122,547
Granted, Shares | shares	69,014
Exercised, Shares | shares	(4,000)
Ending Balance, Shares | shares	187,561
Options Exercisable, Shares | shares	47,079
Beginning Balance, Weighted Average Exercise Price | $ / shares	$ 57.74
Granted, Weighted Average Exercise Price | $ / shares	72.32
Exercised, Weighted Average Exercise Price | $ / shares	5.67
Ending Balance, Weighted Average Exercise Price | $ / shares	64.21
Options Exercisable, Weighted Average Exercise Price | $ / shares	$ 51.55
Ending Balance, Weighted Average Remaining Terms (years)	3 years 8 months 12 days
Options Exercisable, Weighted Average Remaining Terms (years)	2 years 7 months 6 days
Ending Balance, Aggregate Intrinsic Value | $	$ 2,490,355
Options Exercisable, Aggregate Intrinsic Value | $	$ 1,220,858