Stock-Based Compensation - Restricted Stock Unit Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares
Vested (in shares)	(562,777)	(48,890)
Restricted Stock
Shares
Balance at beginning of year (in shares)	1,110,277	1,359,162	1,463,796
Granted (in shares)	228,135		1,090,000
Forfeited (in shares)		(199,995)	(213,001)
Vested (in shares)	(562,777)	(48,890)	(981,633)
Balance at end of year (in shares)	775,635	1,110,277	1,359,162
Weighted Average Grant Date Fair Value
Balance at beginning of year (in dollars per share)	$ 1.21	$ 1.28	$ 2.82
Granted (in dollars per share)	1.52		0.97
Forfeited (in dollars per share)		1.59	2.99
Vested (in dollars per share)	0.98	1.59	2.85
Balance at end of year (in dollars per share)	$ 1.47	$ 1.21	$ 1.28