Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 6,937	$ 1,516
Collaborators [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	6,125	77
Royalties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	781	1,279
Research grants [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	12	100
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 19	$ 60