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Revenue From Contracts With Customers - Schedule of Deferred Revenue by Arrangement (Detail)
3 Months Ended
Mar. 31, 2018
USD ($)
Deferred Revenue [Abstract]  
Beginning balance, January 1, $ 14,448
Amount of deferred revenue recognized in income (4,757)
Additions to deferred revenue 7,639
Ending balance, March 31, $ 17,330