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
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-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

Revenue Recognition (Details) $ in Millions	3 Months Ended		6 Months Ended
Revenue Recognition (Details) $ in Millions	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) distributor	Jun. 30, 2018 USD ($) distributor
Disaggregation of Revenue [Line Items]
Provisions for revenue reserves to reduce product revenues to product revenues, net \| $	$ 26.6	$ 1.7	$ 42.8	$ 1.7
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa
Disaggregation of Revenue [Line Items]
Number of distributors \| distributor			3	3
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa \| Distributor One
Disaggregation of Revenue [Line Items]
Concentration risk percentage			36.00%	34.00%
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa \| Distributor Two
Disaggregation of Revenue [Line Items]
Concentration risk percentage			33.00%	33.00%
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa \| Distributor Three
Disaggregation of Revenue [Line Items]
Concentration risk percentage			28.00%	30.00%