Summary of Significant Accounting Policies - Property, Equipment and Capitalized Software Costs - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2018	Mar. 30, 2018	Mar. 31, 2017	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Capitalized computer software, additions			$ 600
Capitalized software developed for internal use		$ 17,890		$ 23,009
Depreciation and amortization expense		563	387
Capitalized software costs, accumulated amortization		700	300
Gain on sale of building		110
Maximum [Member]
Property Plant And Equipment [Line Items]
Capitalized computer software, additions		100
Capitalized Software [Member]
Property Plant And Equipment [Line Items]
Capitalized software developed for internal use		2,000	1,600
Depreciation and amortization expense		$ 200
Capitalized Software [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Depreciation and amortization expense			$ 100
Property, equipment and capitalized software, useful life		5 years
Capitalized Software [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property, equipment and capitalized software, useful life		2 years
Corporate Administrative Building [Member]
Property Plant And Equipment [Line Items]
Proceeds from sale of building	$ 1,800
Book value of building	1,600
Corporate Administrative Building [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Gain on sale of building	$ 100