Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
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-Publisher FASB
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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Value, before forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

+ References

No definition available.

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Stockholders' Equity - The 2017 Plan, Additional Information (Details) - 2017 Plan - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2019	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)		89,700
Options granted, exercise price (in dollars per share)		$ 13.76
Compensation not yet recognized		$ 3.6
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	89,700
Expiration period	10 years	10 years
Vesting percentage	2.0833%
Fair value of option granted	$ 1.1
Stock based compensation expense		$ 1.0	$ 1.3
Options to purchase common stock \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, exercise price (in dollars per share)	$ 13.61
Options to purchase common stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, exercise price (in dollars per share)	$ 14.62