Summary of Significant Accounting Policies - Research and Development Tax Incentive (Details) $ in Millions	9 Months Ended
Sep. 30, 2018 AUD ($)
Revenue, Practical Expedient [Abstract]
Financing component	true
Maximum \| Australian Taxation Office
Revenue, Practical Expedient [Abstract]
Revenue for availability of research and development tax incentive	$ 20.0

Indicates (true false) whether practical expedient was elected not to adjust consideration for effect of financing component when transfer and customer payment for product or service occurs within one year or less.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130569-203045

Name:	us-gaap_RevenuePracticalExpedientFinancingComponent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration