Goodwill and Other Intangible Assets - Details of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Indefinite-lived Intangible Assets [Line Items]
Total intangible assets	$ 11,227	$ 11,227
Total accumulated amortization	(5,289)	(5,185)
Intangible assets, net	5,938	6,042
Domain Names [Member]
Indefinite-lived Intangible Assets [Line Items]
Total intangible assets	6,327	6,327
Total accumulated amortization	(389)	(285)
Customer Backlog [Member]
Indefinite-lived Intangible Assets [Line Items]
Total intangible assets	4,000	4,000
Total accumulated amortization	(4,000)	(4,000)
Trade Names and Trademarks [Member]
Indefinite-lived Intangible Assets [Line Items]
Total intangible assets	900	900
Total accumulated amortization	$ (900)	$ (900)