Share Based Compensation - Fair Value of PSUs Granted Determined Using Monte Carlo Simulation (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award (in years)	5 years 4 months 24 days	5 years 6 months	5 years 6 months
Volatility	59.30%	59.40%	55.70%
Risk-free interest rate	0.80%	0.40%	1.90%
Expected dividend yield	0.00%	0.00%	0.00%
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price on grant date (in dollars per share)	$ 4.42	$ 2.73	$ 2.92
Performance period starting price (in dollars per share)	$ 3.70	$ 4.78	$ 3.01
Term of award (in years)	2 years 6 months 21 days	2 years 6 months 18 days	2 years 6 months 18 days
Volatility	54.40%	57.50%	63.70%
Risk-free interest rate	0.23%	0.21%	1.79%
Expected dividend yield	0.00%	0.00%	0.00%
Fair value per TSR PSU (in dollars per share)	$ 5.55	$ 2.00	$ 3.18