Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 2,096	$ 1,516
Royalties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	1,619	1,279
Collaborators [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	386	77
Research grants [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	77	100
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 14	$ 60