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Stock-Based Compensation - Stock Option Activity - Narratives (Details) - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Intrinsic value of options exercised during the period	$ 0
On the settlement of employee stock purchase plan shares
Stock-Based Compensation
Granted (shares)	0	0	0
Intrinsic value of options exercised during the period		$ 800,000	$ 300,000
On the settlement of employee stock purchase plan shares \| Maximum
Stock-Based Compensation
Expiration period	7 years
On the settlement of employee stock purchase plan shares \| First anniversary vesting
Stock-Based Compensation
Vesting percentage	33.33%
On the settlement of employee stock purchase plan shares \| Second anniversary vesting
Stock-Based Compensation
Vesting percentage	33.33%
On the settlement of employee stock purchase plan shares \| Third anniversary vesting
Stock-Based Compensation
Vesting percentage	33.33%
Vesting period	3 years