Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2017 USD ($)	Sep. 30, 2017 Customer Reseller	Sep. 30, 2016 Customer Reseller	Sep. 30, 2017 USD ($) Customer Reseller	Sep. 30, 2016 Customer Reseller
Revenue, Major Customer [Line Items]
Number of reseller | Reseller		1	1	1	1
Cumulative effect adjustment to accumulated deficit | $				$ 14
ASU 2016-09 [Member]
Revenue, Major Customer [Line Items]
Cumulative effect adjustment to accumulated deficit | $	$ 2,600
Credit Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Number of customers representing 10% or more of gross accounts receivable | Customer		0	0	0	0
Revenue [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Number of customers representing 10% or more of revenue | Customer		0	0	0	0