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		6 Months Ended
	Jan. 06, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 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		199,422	198,000	1,695,755	205,500
Weighted-average grant date fair value		$ 3.13	$ 3.06	$ 1.80	$ 3.06
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		$ 400,000	$ 500,000	$ 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		5,600,000		$ 5,600,000
Expected recognition period				1 year 6 months 29 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		$ 3,300,000		$ 3,300,000
Expected recognition period				1 year 6 months 14 days