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Revenue - Summary of Changes in Deferred Revenue Related to Material Right Performance Obligations (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Revenue From Contract With Customer [Abstract]    
Balance, beginning of period $ 76,244 $ 64,651
Deferral of revenue 5,885 5,561
Recognition of unearned revenue (3,674) (2,701)
Balance, end of period $ 78,455 $ 67,511