General and Administrative Expenses - Schedule of General and Administrative Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
General And Administrative Expense [Abstract]
Salaries and benefits	$ 31,553	$ 39,565	$ 11,721
Stock-based compensation expenses	20,491	26,499	18,926
Other expenses	17,869	16,649	8,152
Professional fees	12,773	21,189	7,557
Loss on disposal of property and equipment	1,851	2,436	190
Travel expenses	937	4,565	2,031
Credit loss expenses	409
Total	$ 85,883	$ 110,903	$ 48,577