Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(8))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(10))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Name:	us-gaap_IncomeTaxReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

United Kingdom (U.K.) Research and Development Incentives (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Claim for refundable cash credit		$ 19.7
U.K. Tax Legislation \| U.K. Tax Legislation
Operating Loss Carryforwards [Line Items]
Window to seek relief under U.K. tax legislature	2 years
Tax Year 2017
Operating Loss Carryforwards [Line Items]
Claim for refundable cash credit		9.9
Tax Year 2018
Operating Loss Carryforwards [Line Items]
Claim for refundable cash credit		$ 9.8