Commitments and Contingencies - Additional Information (Detail)		1 Months Ended			9 Months Ended
	Dec. 09, 2015 USD ($)	Oct. 31, 2015 ft²	Sep. 30, 2015 Patent	Jul. 31, 2013 ft²	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2015 EUR (€) ft²	Apr. 30, 2014 USD ($)
Commitments and Contingencies [Line Items]
Office space under operating lease | ft²					120,500	120,500
Purchase price of property amount	$ 16,500,000
Transaction closing date for purchasing of property					2016-04
License agreement, upfront payment					$ 500,000		$ 1,500,000
License agreement, maximum agreed additional payments upon achievement of development milestones					2,800,000		$ 4,500,000
License agreement, milestone payment					600,000
Patents allegedly infringed upon, number | Patent			2
Europe
Commitments and Contingencies [Line Items]
Facilities leases, base rent per month					70,000	€ 64,500
Europe | Lease Agreements
Commitments and Contingencies [Line Items]
Office space under operating lease | ft²				33,000
Lease, expiration date				Jul. 31, 2023
Additional office space under operating lease | ft²		9,000
Europe | Lease Agreement Adjacent to Aachen Facility
Commitments and Contingencies [Line Items]
Office space under operating lease | ft²		30,000
Lease, expiration date		Jun. 30, 2016
For May 2014 through December 2015
Commitments and Contingencies [Line Items]
Facilities leases, base rent per month					74,050
For January 2016 through February 2016
Commitments and Contingencies [Line Items]
Facilities leases, base rent per month					85,818
For March 2016 through February 2018
Commitments and Contingencies [Line Items]
Facilities leases, base rent per month					82,518
For March 2018 through February 2021
Commitments and Contingencies [Line Items]
Facilities leases, base rent per month					$ 85,030