Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 18, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 12, 2018	Feb. 15, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted			300,500	593,500	506,000	859,000
Weighted-average grant date fair value			$ 2.11	$ 4.29	$ 2.49	$ 4.34
Additional stock-based compensation expense					$ 481
Accelerated vested of restricted Shares	34,516
Adjustment of restricted vested amount			$ 12		$ 12
Stock options granted exercise price					$ 3.50
Director One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life	92,500
Director Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life	167,500
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life							117,500
Additional stock-based compensation expense			117		$ 117
Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Extended contractual life								751,667
Outside 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted		500,000
Stock options granted exercise price		$ 6.19
Unvested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested restricted stock outstanding			4,100		$ 4,100
Expected recognition period					1 year 6 months 18 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period					1 year 5 months 23 days
Unrecognized stock-based compensation expense related to unvested restricted stock			$ 3,500		$ 3,500