Summary of Significant Accounting Policies - Minimum Future Licensing Revenue (Detail) (Fiber Optic Licensing and Other [Member], Minimum [Member], Scenario Forecast [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended					84 Months Ended	144 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2026	Dec. 31, 2025
Fiber Optic Licensing and Other [Member] | Minimum [Member] | Scenario Forecast [Member]
License And Collaboration Agreements [Line Items]
Fixed non-cancelable minimum licensing revenues	$ 32,775	$ 48,950	$ 62,348	$ 74,933	$ 90,549	$ 124,739	$ 434,294