Summary of Significant Accounting Policies - Reconciliation of Shares Used to Determine Net Income per Share (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share Disclosure [Line Items]
Net income	$ 8,525	$ 4,830	$ 14,259	$ 7,774
Weighted average number of shares - basic	41,567,848	33,128,518	41,537,894	33,008,588
Weighted average number of shares outstanding - diluted	43,550,226	34,270,337	43,490,914	34,045,125
Warrants [Member]
Earnings Per Share Disclosure [Line Items]
Shares underlying	0	156,244	0	129,351
Options [Member]
Earnings Per Share Disclosure [Line Items]
Shares underlying	1,982,378	985,575	1,953,020	907,186