Goodwill and Intangible Assets - Schedule of Acquired Intangible Assets by Major Asset Class (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross	$ 1,353	$ 1,353
Accumulated amortization	(704)	(455)
Net book value before impairment	649	898
Impairment charge	(411)	(411)
Net book value	$ 238	487
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	6 years
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	$ 265	265
Accumulated amortization	(125)	(78)
Net book value before impairment	140	187
Net book value	$ 140	187
Purchased Technology [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years
Purchased Technology [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	6 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	$ 999	999
Accumulated amortization	(499)	(324)
Net book value before impairment	500	675
Impairment charge	(411)	(411)
Net book value	$ 89	264
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	3 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	6 years
Trademarks/Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	2 years
Gross	$ 38	38
Accumulated amortization	$ (38)	(28)
Net book value before impairment		10
Net book value		10
Non-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	3 years
Gross	$ 51	51
Accumulated amortization	(42)	(25)
Net book value before impairment	9	26
Net book value	$ 9	$ 26