Stock-based Compensation - Additional Information (Details) - Restricted common shares - 2013 Plan - shares	Apr. 30, 2019	Aug. 07, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized (in shares)	7,000,000	2,450,000	600,000
Increase in number of common shares authorized for issuance (in shares)	4,550,000	1,850,000

Number of shares authorized for issuance under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant