Common Stock and Warrants - Summary of Warrant Activity (Detail)	9 Months Ended		12 Months Ended
	Dec. 31, 2016 $ / shares shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 31, 2017 $ / shares shares
Class Of Warrant Or Right [Line Items]
Number of Warrants, Outstanding, ending balance			2,354,908	2,354,908
CAD
Class Of Warrant Or Right [Line Items]
Number of Warrants, Outstanding, beginning balance	1,686,000	1,686,000	1,111,530	1,111,530
Number of Warrants, Granted	1,030,587	1,030,587	25,063	25,063
Number of Warrants, Granted (Agent Compensation)	100,291	100,291
Number of Warrants, Expired	(1,320,880)	(1,320,880)
Number of Warrants, Exercised	(384,468)	(384,468)	(125,088)	(125,088)
Number of Warrants, Outstanding, ending balance	1,111,530	1,111,530
Number of Warrants, Outstanding and exercisable, ending balance			1,011,505	1,011,505
Weighted-Average Exercise Price, Outstanding, beginning balance | $ / shares		$ 5.00		$ 7.30
Weighted-Average Exercise Price, Granted | $ / shares		7.50		7.50
Weighted-Average Exercise Price, Granted (Agent Compensation) | $ / shares		5.00
Weighted-Average Exercise Price, Expired | $ / shares		5.00
Weighted-Average Exercise Price, Exercised | $ / shares		5.10		6.50
Weighted-Average Exercise Price, Outstanding, ending balance | $ / shares		$ 7.30
Weighted-Average Exercise Price, Outstanding and exercisable, ending balance | $ / shares				$ 7.38
USD
Class Of Warrant Or Right [Line Items]
Number of Warrants, Outstanding, beginning balance	905,721	905,721	905,721	905,721
Number of Warrants, Granted			646,016	646,016
Number of Warrants, Exercised			(208,333)	(208,333)
Number of Warrants, Outstanding, ending balance	905,721	905,721
Number of Warrants, Outstanding and exercisable, ending balance			1,343,404	1,343,404
Weighted-Average Exercise Price, Outstanding, beginning balance | $ / shares	$ 8.10		$ 8.10
Weighted-Average Exercise Price, Granted | $ / shares			12.25
Weighted-Average Exercise Price, Exercised | $ / shares			7.20
Weighted-Average Exercise Price, Outstanding, ending balance | $ / shares	$ 8.10
Weighted-Average Exercise Price, Outstanding and exercisable, ending balance | $ / shares			$ 10.25