Nature of Business and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Customer Segment	Dec. 31, 2014 USD ($) Customer	Dec. 31, 2013 USD ($) Customer
Schedule Of Significant Accounting Policies [Line Items]
Realized and unrealized foreign currency transaction gain recognized in earnings	$ 0.7	$ 1.2
Realized and unrealized foreign currency transaction loss recognized in earnings			$ 0.2
Accrued rent	5.4	5.3
Accrued rent included in other long term liabilities	4.8	4.7
Accrued rent included in other current liabilities	0.6	$ 0.6
Aggregate gross selling price of shipments	25.0
Payment received on shipment	$ 23.5
Number Of customers accounted for accounts receivable | Customer	1	1
Advertising costs	$ 0.1	$ 0.6	$ 1.0
Number of operating segments | Segment	1
Reclassification of deferred debt issuance costs to long term debt	$ 0.8
Royalty financing	50.0
Convertible note	200.0
Outside the United States
Schedule Of Significant Accounting Policies [Line Items]
Long lived assets	$ 1.4	$ 1.4
Net product revenue
Schedule Of Significant Accounting Policies [Line Items]
Number of customers accounted for net product sales | Customer	1	1	3
Net product revenue | Customer One Product Sales
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage	76.00%	72.00%	24.00%
Net product revenue | Customer Two Product Sales
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage			15.00%
Net product revenue | Customer Three Product Sales
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage			13.00%
Net product revenue | Outside the United States
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage	25.00%	28.00%	9.00%
Net product revenue | Outside the United States | Germany
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage	9.00%	19.00%	7.00%
Accounts receivable | Customer One Product Sales
Schedule Of Significant Accounting Policies [Line Items]
Customers concentration risk, percentage	61.00%	75.00%
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment, useful life	10 years
Capitalized costs, amortization period maximum	17 years
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Property and equipment, useful life	3 years