Stock-Based Compensation - Employee Stock Purchase Plan (Details) - 2018 ESPP - shares	1 Months Ended	3 Months Ended
Jan. 31, 2019	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares available for issuance (in shares)	851,634
Issuance of common stock in connection with employee stock purchase plan (in shares)		280,308

Number of shares issued during the period as a result of an employee stock purchase plan.

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Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration