Summary of Effects of Adopting Topic 606 on Consolidated Statement of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net revenue	$ 78,142	$ 60,219
Cost of revenue	44,810	38,059
Operating expenses	35,197	26,790
Provision for income taxes	(155)	214
Net loss	(4,703)	(8,152)
Net loss attributable to common stockholders	$ (5,541)	$ (8,138)
Basic and diluted net loss per share:
Basic	$ (0.35)	$ (0.61)
Diluted	$ (0.35)	$ (0.61)
Topic 606 | Adjustments
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net revenue	$ 1
Net loss	1
Net loss attributable to common stockholders	1
Topic 606 | Balance Under Prior GAAP
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net revenue	78,143
Cost of revenue	44,810
Operating expenses	35,197
Provision for income taxes	(155)
Net loss	(4,702)
Net loss attributable to common stockholders	$ (5,540)
Basic and diluted net loss per share:
Basic	$ (0.35)
Diluted	$ (0.35)