Commitments and Contingencies - Additional Information (Detail)	1 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 31, 2014 USD ($)	Apr. 30, 2014 USD ($)	May. 31, 2013 USD ($) shares	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2012 USD ($)	Feb. 28, 2015 CAD	Feb. 28, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Upfront payment paid								$ 300,000
Payment in cash upon closing of financing		$ 11,000,000
Minimum financing		35,000,000
Milestone payment upon regulatory authority approval		$ 3,000,000
Manufacturing costs obligation	$ 100,000
Milestone payment not accrued				$ 3,000,000		$ 3,000,000
Collateralized restricted deposit				200,000		200,000					$ 75,000
Payments to contract research organization				900,000		$ 2,400,000
Novosom License Agreement [Member]
Loss Contingencies [Line Items]
Shares of common stock issued in settlement of first milestone payment | shares			2,108,870
Fair marker value of common stock issued			$ 100,000
Operating Lease Agreement To Sublease Office Space [Member] | Vancouver [Member]
Loss Contingencies [Line Items]
Operating lease agreement expiration date						Feb. 27, 2018
Letter of credit issued | CAD									CAD 50,000
Collateralized restricted deposit										$ 50,000
Vancouver Facility [Member]
Loss Contingencies [Line Items]
Total rent expense for operating leases				$ 100,000	$ 17,000	$ 200,000	$ 39,000
Maximum [Member]
Loss Contingencies [Line Items]
Aggregate milestone payment								$ 14,500,000