Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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

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Stock-based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)						7,150,000
Stock-based compensation expense	$ 0.9	$ 1.0	$ 2.7	$ 2.1
Share-based compensation, nonvested awards, compensation cost not yet recognized	$ 5.3		$ 5.3
Period for recognition of compensation on unvested stock option (in years)			1 year 10 months 24 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)					500,000
Shares issued (in shares)			253,042