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Stock-based Compensation - Plan Description (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020
2003 Stock Incentive Plan, as amended and restated
Stock-based compensation
Number of additional shares authorized		26
Number of shares authorized for plan as a percentage of stock outstanding	15.00%
Shares authorized	30,200		2,100,443
Shares available for grant			2,100,397
2003 Stock Incentive Plan, as amended and restated \| Minimum
Stock-based compensation
Purchase price of common stock (as a percent)	100.00%
2003 Stock Incentive Plan, as amended and restated \| Principal (10 percent) owner \| Minimum
Stock-based compensation
Purchase price of common stock (as a percent)	110.00%
2003 Stock Incentive Plan, as amended and restated \| Stock options
Stock-based compensation
Award vesting period	4 years
2003 Stock Incentive Plan, as amended and restated \| Stock options \| Maximum
Stock-based compensation
Option expiration period	10 years
Inducement grants \| Maximum
Stock-based compensation
Award vesting period	4 years