Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents		$ 0
Spero Potentiator Australia Pty Limited [Member] \| Research and Development Expenses [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of refundable tax incentive	43.50%

Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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