Stock-Based Compensation, Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Shares Outstanding, Beginning balance (in shares)	5,543
Granted	1,697
Exercised	(102)
Forfeited or expired	(159)
Stock Options Shares Outstanding, Ending balance (in shares)	6,978	5,543
Options exercisable (in shares)	4,090
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Stock Option Outstanding, Weighted Average Exercise Price, Beginning balance (in usd per share)	$ 20.13
Granted	18.43
Exercised	13.98
Forfeited	22.52
Stock Option Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share)	19.75	$ 20.13
Options Exercisable, Weighted Average Exercise Price (in usd per share)	$ 19.15
Stock Options Outstanding, Weighted Average Remaining Contractual Term	6 years 11 months 15 days	6 years 3 months
Options exercisable, Weighted Average Remaining Contractual Term	5 years 4 months 13 days
Stock Options Outstanding, Aggregate Intrinsic Value, Beginning balance	$ 16,043
Stock Options Outstanding, Aggregate Intrinsic Value, Ending balance	19	$ 16,043
Options exercisable, Aggregate Intrinsic Value	$ 19

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.