Description of Business (Details Textual) - USD ($)	1 Months Ended	3 Months Ended				9 Months Ended
	Mar. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Description of Business [Line Items]
Royalty Revenues From Sales Percentage		100.00%			61.00%	13.00%	70.00%
Royalty Revenue, Total		$ 151,000			$ 1,965,000	$ 8,366,000	$ 7,461,000
Other Receivables, Net, Current		3,500,000				3,500,000		$ 0
Payment Of Milestone Payments						7,000,000
Merck Co Inc [Member]
Description of Business [Line Items]
Decreases Of Royalty Revenues		$ 0	$ 563,000			$ 564,000
Proceeds from Royalties Received	$ 770,000		335,000	$ 636,000
Nektar Therapeutics, Inc [Member]
Description of Business [Line Items]
Royalty Revenues From Sales Percentage						13.00%
Royalty Revenue, Total			7,000,000			$ 7,000,000
Proceeds from Royalties Received			3,500,000
Other Receivables, Net, Current			$ 3,500,000