Earnings Per Share - Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income (loss)									$ 10,722	$ (2,740)
Dividends paid to preferred stockholders									(119)	(404)
Net income (loss) available to common stockholders									$ 10,603	$ (3,144)
Denominator:
Weighted average shares outstanding - basic	38,501	36,094	32,068	31,297	26,925	25,020	21,888	15,299	34,513	22,322
Potential common shares - options (treasury stock method)									2,478
Weighted average shares outstanding - diluted	41,767	39,472	35,308	31,323	27,395	25,020	21,888	15,299	36,991	22,322
Shares excluded due to an exercise price greater than weighted average stock price for the period									88	1,081
Earnings (loss) per common share:
Basic	$ 0.10	$ 0.10	$ 0.11		$ 0.10	$ (0.04)	$ (0.10)	$ (0.16)	$ 0.31	$ (0.14)
Diluted	$ 0.09	$ 0.09	$ 0.10		$ 0.10	$ (0.04)	$ (0.10)	$ (0.16)	$ 0.29	$ (0.14)