Summary of Significant Accounting Policies - Research and Development (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Research and Development
Prepaid research and development costs	$ 1.1	$ 0.4

The current portion of prepayments received from customers for goods or services to be provided in the future.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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