Income Taxes - Income Tax Provision (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 0	$ 0
State	0	0
Foreign	0	0
Total current federal, state provision for income tax	0	0
Deferred:
Federal	0	0
State	0	0
Foreign	0	0
Total deferred federal, state provision for income tax	0	0
Total provision for income taxes	$ 0	$ 0	$ 0