For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Summary of Significant Accounting Policies (Revenue Recognition) (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
One collaboration partner [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage		60.00%	43.00%	87.00%
ASC 606 [Member]
Concentration Risk [Line Items]
Decrease in accumulated deficit	$ (8.9)		$ (5.7)
Deferred revenue, Period increase (decrease), current portion	(3.0)		(1.0)
Deferred revenue, Period increase (decrease), net of portion	$ (5.9)		(4.7)
Decrease in research and development revenue			$ 3.2