Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Defined contribution, plan name		401(k)
Defined contribution retirement plan, description		All employees over the age of 21 are eligible to participate in the plan at the beginning of the calendar quarter after three consecutive months of service.
Employer contributions to the plan		$ 198	$ 174	$ 118
Defined contribution retirement plan, employer contribution percentage	3.00%
Minimum [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined contribution retirement plan, employee eligible age to participate		21 years
Defined contribution retirement plan, employee eligible service period		3 months