Revenue Recognition - Estimated Revenue Expected to be Recognized in Future Related to Performance Obligations (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Remainder of 2017 [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	3 months
Remainder of 2017 [Member] | Software [Member] | Third-Party Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 35
Remainder of 2017 [Member] | Software [Member] | Proprietary Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 117
2018
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	1 year
2018 | Software [Member] | Third-Party Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 110
2018 | Software [Member] | Proprietary Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 470
2019
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	1 year
2019 | Software [Member] | Third-Party Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 36
2019 | Software [Member] | Proprietary Software [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 313