Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 02, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on pooled patents agreement	$ 21,000,000	$ 0
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount	21,000,000	0
Collaborative Arrangement | Chinese University of Hong Kong
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Collaborative Arrangement, Aggregate Consideration, Up-front Payment			6,150,000
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount			43,850,000
Physical Samples | Collaborative Arrangement | Chinese University of Hong Kong
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount			21,000,000
Settlements Of Claims And Disputes | Collaborative Arrangement | Chinese University of Hong Kong
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount			$ 1,850,000