Number of shares issued pursuant to the terms of a deferred compensation arrangement.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Stock-Based Compensation - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Jan. 06, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 13, 2019	May 12, 2018	Feb. 15, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted		140,000	300,500	1,835,755	506,000
Weighted-average grant date fair value		$ 3.05	$ 2.11	$ 1.90	$ 2.49
Number of shares issued for accrued annual performance bonus	446,428
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life						52,500	117,500
Director One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life						126,700
Additional stock-based compensation expense		$ 0		$ 400,000	$ 500,000
Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life								751,667
Unvested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested restricted stock outstanding		6,700,000		$ 6,700,000
Expected recognition period				1 year 9 months 10 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested restricted stock outstanding		$ 2,800,000		$ 2,800,000
Expected recognition period				1 year 5 months 23 days