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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 2: 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 3: 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=121572278&loc=d3e13531-108611

Reference 4: 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=121572278&loc=d3e13537-108611

Reference 5: 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		9 Months Ended
Revenue Recognition (Details) $ in Millions	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) distributor	Sep. 30, 2019 USD ($) distributor
Disaggregation of Revenue [Line Items]
Provisions for revenue reserves to reduce product revenues to product revenues, net \| $	$ 52.1	$ 31.0	$ 141.9	$ 73.8
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa and Rocklatan
Disaggregation of Revenue [Line Items]
Number of distributors \| distributor			3	3
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa and Rocklatan \| Distributor One
Disaggregation of Revenue [Line Items]
Concentration risk percentage			36.00%	37.00%
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa and Rocklatan \| Distributor Two
Disaggregation of Revenue [Line Items]
Concentration risk percentage			34.00%	31.00%
Customer Concentration Risk \| Sales Revenue, Net \| Rhopressa and Rocklatan \| Distributor Three
Disaggregation of Revenue [Line Items]
Concentration risk percentage			29.00%	30.00%