Revenue Recognition - Summary of Transaction Price Allocated to Future Performance Obligations (Detail) $ in Thousands	Mar. 31, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	$ 27,086
Deferred Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	17,261
Unbilled Backlog [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	9,825
Current [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	20,232
Current [Member] | Deferred Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	15,889
Current [Member] | Unbilled Backlog [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	4,343
Long-term [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	6,854
Long-term [Member] | Deferred Revenue [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	1,372
Long-term [Member] | Unbilled Backlog [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total	$ 5,482