Share Capital - Schedule of Conditional Capital Reserved for Future Issuance (Detail) - shares	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Conditional capital reserved for future issuance	15,325,607	2,444,364
Charpentier Call Option [Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance		328,017
Unvested Unissued Restricted Stock [Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance	166,667	142,794
Outstanding Stock Options [Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance	4,535,371	1,939,986
Stock Option Plan [Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance	5,290,643	33,567
Bonds and Similar Debt Instruments[Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance	4,919,700
Employee Purchase Plans [Member]
Class of Stock [Line Items]
Conditional capital reserved for future issuance	413,226