Restructuring Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Aug. 31, 2013 Employees	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Charges for employee termination benefits		$ 2.2
Restructured of employees to conserve capital include a staff reduction of employees	47
Research and development [Member]
Restructuring Cost and Reserve [Line Items]
Charges for employee termination benefits		1.2
Asset impairment charge		0.7
Manufacturing and production [Member]
Restructuring Cost and Reserve [Line Items]
Charges for employee termination benefits		0.5
General and administrative [Member]
Restructuring Cost and Reserve [Line Items]
Charges for employee termination benefits		$ 0.5