Collaborative and Other Agreements (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Licensing Payments Received	$ 29,000	$ 143,000	$ 238,000	$ 347,000
Intrexon Corporation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
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	0	37,000	76,000	81,000
Cash Paid For Channel Collaboration Agreement	0	40,000	117,000	75,000
Liability for amounts due to terminated channel collaboration partner	15,000		15,000
University Of Leicester [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expenses Incurred Under Channel Collaborative Agreement	41,000	68,000	127,000	156,000
Cash Paid For Channel Collaboration Agreement	0	55,000	140,000	219,000
University Of Glasgow [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expenses Incurred Under Channel Collaborative Agreement	0	0	0	13,000
Cash Paid For Channel Collaboration Agreement	0	0	0	61,000
Walter Reed Army Institute Of Research [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payments For Services Under Collaborative Agreement	0	0	0	$ 0
Takara Bio Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Licensing Payments Received		$ 40,000
Patent license agreement revenue	$ 4,000		$ 11,000
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
Common Stock [Member] | Intrexon Corporation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Stock Issued During Period, Value, Issued for Services					$ 3,000,000