Commitments and Contingencies - Additional Information (Detail)				1 Months Ended		9 Months Ended	12 Months Ended
	Jan. 31, 2015 USD ($)	Nov. 10, 2014 USD ($)	Nov. 19, 2010 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2015 USD ($) Milestone	Dec. 31, 2014 USD ($) Milestone
Other Commitments [Line Items]
Claims paid to date related to indemnification issues						$ 0
Accruals or expenses related to indemnification issues						$ 0	$ 0
FoxKiser,LLP [Member]
Other Commitments [Line Items]
Lease expiration date						Apr. 30, 2015
Monthly lease payments	$ 20,000
ARIAD Pharmaceuticals, Inc [Member]
Other Commitments [Line Items]
Annual maintenance fees			$ 50,000			$ 0	$ 0
Number of milestone | Milestone						0	0
Milestone payments						$ 0	$ 0
Royalty expense incurred						0
Sublicense fees						$ 0
ARIAD Pharmaceuticals, Inc [Member] | Common Class A [Member]
Other Commitments [Line Items]
Fair value of stock issued for license			726,000
ARIAD Pharmaceuticals, Inc [Member] | Maximum [Member]
Other Commitments [Line Items]
Contractual obligation			$ 2,300,000
Regents of the University of Minnesota [Member]
Other Commitments [Line Items]
Annual maintenance fees		$ 9,000
Number of milestone | Milestone						0	0
Milestone payments						$ 0	$ 0
Royalty expense incurred						0
Sublicense fees						$ 0
Up-front fee paid		25,000
Regents of the University of Minnesota [Member] | Maximum [Member] | Annual License Maintenance Fee [Member]
Other Commitments [Line Items]
Contractual obligation		15,000
Regents of the University of Minnesota [Member] | Maximum [Member] | Royalties And Sublicense Fees [Member]
Other Commitments [Line Items]
Contractual obligation		125,000
Regents of the University of Minnesota [Member] | Minimum [Member] | Annual License Maintenance Fee [Member]
Other Commitments [Line Items]
Contractual obligation		$ 5,000
Philadelphia, Pennsylvania [Member]
Other Commitments [Line Items]
Operating lease renewal period						6 years
Lease expiration date						Dec. 31, 2015
Monthly lease payments						$ 4,000
Rockville, Maryland [Member]
Other Commitments [Line Items]
Lease expiration date					Sep. 30, 2020
Monthly lease payments				$ 41,000	$ 24,000
Lease period				5 years	5 years 6 months
Options to extend the lease					6 years
Lease commenced date					2015-04
Lease term						Extend the term of the existing lease to October 2020