Revenue Recognition - Estimated Revenue Expected to be Recognized in Future Related to Performance Obligations (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue, expected recognition period	1 year
Software [Member] | Third Party Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 24
Software [Member] | Third Party Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	50
Software [Member] | Third Party Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	14
Software [Member] | Proprietary Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	853
Software [Member] | Proprietary Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	1,827
Software [Member] | Proprietary Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	1,802
Software [Member] | Proprietary Software [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	687
Professional Engineering Service [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Estimated revenue expected to be recognized in future	$ 230