Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020	Jan. 01, 2019
Stock Options
Stock Options, Outstanding Beginning Balance (in shares)	420	603			450	613
Stock Options, Granted (in shares)	10	18
Stock Options, Exercised (in shares)		(16)
Stock Options, Forfeited (in shares)	(40)	(12)
Stock Options, Outstanding Ending Balance (in shares)	420	603			450	613
Stock Options, Exercisable (in shares)	397	477
Grant Date Weighted- Average Exercise Price
Grant Date Weighted-Average Exercise Price, Beginning balance (in USD per share)	$ 2.78	$ 2.86			$ 2.78	$ 2.85
Grant Date Weighted Average Exercise Price, Granted (in USD per share)	1.88	2.91
Grant Date Weighted Average Exercise Price, Exercised (in USD per share)		2.59
Grant Date Weighted Average Exercise Price, Forfeited (in USD per share)	2.58	3.05
Grant Date Weighted-Average Exercise Price, Ending balance (in USD per share)	2.78	2.86			$ 2.78	$ 2.85
Grant Date Weighted Average Exercise Price, Exercisable (in USD per share)	$ 2.81	$ 2.87
Weighted- Average Remaining Contractual Life (in Years)
Weighted Average Remaining Contractual Life (Years), Beginning Balance	2 years 1 month 13 days	2 years 4 months 2 days	2 years 5 months 8 days	3 years 2 months 4 days
Weighted Average Remaining Contractual Life (Years), Granted	7 years	7 years
Weighted Average Remaining Contractual Life (Years), Ending Balance	2 years 1 month 13 days	2 years 4 months 2 days	2 years 5 months 8 days	3 years 2 months 4 days
Weighted Average Remaining Contractual Life (Years), Exercisable	1 year 11 months 4 days	2 years 2 months 19 days
Intrinsic Value
Intrinsic Value, Outstanding Beginning Balance	$ 0	$ 57			$ 27	$ 0
Intrinsic Value, Grants in Period	0	0
Intrinsic Value, Forfeitures in Period	0	0
Intrinsic Value, Outstanding Ending Balance	0	57			$ 27	$ 0
Intrinsic Value, Exercisable End of Period	$ 0	$ 0