Collaborative and Other Agreements (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Licensing Payments Received	$ 128,000	$ 143,000	$ 102,000	$ 102,000	$ 101,000	$ 103,000	$ 101,000	$ 104,000	$ 475,000	$ 409,000
Intrexon Corporation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Value of common stock paid for technology access fee											$ 3,000,000
Fees Payable Upon Commencement Of The First Phase 2 Trial	2,500,000								2,500,000
Fees Payable Upon First Regulatory Approval	$ 5,000,000								5,000,000
Expenses Incurred Under Channel Collaborative Agreement									178,000	862,000
Cash Paid For Channel Collaboration Agreement									125,000	941,000
University Of Leicester [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expenses Under Collaborative Agreement									265,000	232,000
Cash Paid For Collaboration Agreement									$ 290,000	182,000
Collaborative Agreement Expiration Date									Nov. 12, 2018
University Of Glasgow [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expenses Under Collaborative Agreement									$ 61,000	184,000
Walter Reed Army Institute Of Research [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payments For Services Under Collaborative Agreement									0	$ 207,000
Takara Bio Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Licensing Payments Received									$ 40,000
Takara Bio Inc [Member] | Nonsoftware License Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percent of License Product Sales Receivable									12.00%
Percent of License Product Service Revenues Receivable									6.00%
Minimum Annual Royalty Payments Receivable									$ 15,000
Takara Bio Inc [Member] | Nonsoftware License Arrangement [Member] | Criteria One [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent Licensing Receivable									30,000
Licensed Product Revenues Milestone Benchmark									1,000,000
Takara Bio Inc [Member] | Nonsoftware License Arrangement [Member] | Criteria Two [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent Licensing Receivable									40,000
Licensed Product Net Sales Milestone Benchmark									$ 2,000,000