Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended		3 Months Ended
	Sep. 02, 2012	May 15, 2011	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Description Of Business And Significant Accounting Policies [Line Items]
Reverse stock split ratios	0.2000	0.1667
VAT receivable			$ 5.4		$ 8.1
Anti-dilutive shares not included in calculation of diluted net loss per share			11.5	8.4
ITALY
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable			5.1
Minimum | Europe
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable, collection period			3 months
Minimum | ITALY
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable, collection period			3 years
Maximum | Europe
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable, collection period			5 years
Maximum | ITALY
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable, collection period			5 years
Other Assets
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable			5.0		5.1
Prepaid Expenses and Other Current Assets
Description Of Business And Significant Accounting Policies [Line Items]
VAT receivable			$ 0.4		$ 3.0
Aequus Biopharma, Inc
Description Of Business And Significant Accounting Policies [Line Items]
Interest in majority-owned subsidiary			61.00%