Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits from stock option activity or stock-based compensation expense recognized in cash flows from operations	$ 0	$ 0	$ 0	$ 0
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding			4,450,517
Number of Options, Granted	345,000	20,000	1,165,350	1,218,000
Number of Options, Exercised			(52,493)
Number of Options, Expired			(170,581)
Number of Options, Forfeited			(127,151)
Number of Options, Outstanding	5,265,642		5,265,642
Number of Options, Options exercisable	2,960,041		2,960,041
Weighted-Average Exercise Price, Outstanding			$ 14.73
Weighted-Average Exercise Price, Granted			16.40
Weighted-Average Exercise Price, Exercised			12.78
Weighted-Average Exercise Price, Expired			13.87
Weighted-Average Exercise Price, Forfeited			16.55
Weighted-Average Exercise Price, Outstanding	$ 15.10		$ 15.10
2019 Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Granted	0		0