Financial Instruments - Schedule of Maintenance Fee Payment to CCKF (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
Related Party Transactions [Abstract]
Maintenance Fee Payments	$ 436	$ 859	$ 1,443	[1]

[1] During the first quarter of 2020, the Company prepaid maintenance payments for the full year 2020, of which approximately $0.4 million and $0.8 million was recognized as expense for the quarter and year to date ended June 30, 2020, respectively