Stock Options and Restricted Stock - Summary of Activity for Restricted Stock Programs (Detail) - $ / shares		3 Months Ended						9 Months Ended			12 Months Ended
		Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020		Sep. 30, 2020		Sep. 30, 2019	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant price per share, cancelled, lower limit		$ 2.61		$ 2.22
Grant price per share, cancelled, upper limit		$ 5.27		$ 5.58
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, beginning balance		362,943	[1]	363,639		284,879		284,879		190,915	190,915
Number of shares, granted						165,674		165,674		178,266	216,148
Number of shares, cancelled		(2,273)		(696)		(5,577)					(3,946)
Number of shares, vested	[2]	(8,055)				(81,337)					(118,238)
Number of shares, ending balance		352,615	[1]	362,943	[1]	363,639		352,615	[1]		284,879
Grant price per share, lower range limit beginning balance		$ 4.39	[1]	$ 4.39		$ 3.95		$ 3.95		$ 2.14	$ 2.14
Grant price per share, upper range limit beginning balance		7.25	[1]	7.25		7.25		7.25		5.27	5.27
Grant price per share, granted, lower limit				6.55							4.80
Grant price per share, granted, upper limit				7.03							7.25
Grant price per share, cancelled, lower limit		6.55		6.55		3.95					3.93
Grant price per share, cancelled, upper limit		7.25		7.25		7.25					6.55
Grant price per share, vested, lower limit	[2]	4.80				3.95					2.06
Grant price per share, vested, upper limit	[2]	5.27				6.55					4.80
Grant price per share, lower range limit ending balance		4.39	[1]	4.39	[1]	4.39		4.39	[1]		3.95
Grant price per share, upper range limit ending balance		7.25	[1]	7.25	[1]	7.25		7.25	[1]		7.25
Grant price per share, granted						6.68
Weighted average grant price beginning balance		6.44	[1]	6.44	[1]	6.01		6.01		$ 4.06	4.06
Weighted average grant price, granted						6.68					6.59
Weighted average grant price, cancelled		6.99		6.97		6.67					4.97
Weighted average grant price, vested	[2]	4.97				5.41					3.89
Weighted average grant price, ending balance		$ 6.47	[1]	$ 6.44	[1]	$ 6.44	[1]	$ 6.47	[1]		$ 6.01

[1] The aggregate fair value of the restricted stock was $882,000 as of September 30, 2020. The remaining vesting period was 2.05 years at September 30, 2020.

[2] The aggregate fair value of the restricted stock vested was $25,000 and $579,000 for the three and nine months ended September 30, 2020, and was $0 and $736,000 for the three and nine months ended September 30, 2019.