Stock-Based Compensation - Information About Stock Options Outstanding and Exercisable (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of Shares Outstanding [Roll Forward]
Option Balances, beginning of period (in shares)	181,385
Options Granted (in shares)	6,067
Options Exercised (in shares)	(9,376)
Options Forfeited (in shares)	(506)
Options Expired (in shares)	(23,693)
Option Balances, end of period (in shares)	153,877	181,385
Options Exercisable end of period (in shares)	124,855
Options, Weighted Average Exercise Price [Roll Forward]
Option Balances, beginning of period (in dollars per share)	$ 4.98
Options Granted (in dollars per share)	6.14
Options Exercised (in dollars per share)	3.89
Options Forfeited (in dollars per share)	4.34
Options Expired (in dollars per share)	7.26
Option Balances, end of period (in dollars per share)	4.75	$ 4.98
Options Exercisable, end of period (in dollars per share)	4.61
Weighted Average Grant Date Fair Value [Roll Forward]
Option Balances, beginning of period	1.30
Options Granted	1.65
Options Exercised	0.94
Options Forfeited	0.87
Options Expired	2.33
Option Balances, end of period	1.18	$ 1.30
Options Exercisable, end of period	$ 1.19
Options, Additional Disclosures [Abstract]
Aggregate intrinsic value, outstanding, beginning of period	$ 158
Aggregate intrinsic value, granted	0
Aggregate intrinsic value, exercised	0
Aggregate intrinsic value, forfeited	0
Aggregate intrinsic value, expired	0
Aggregate intrinsic value, outstanding, end of period	208	$ 158
Aggregate intrinsic value, exercisable, end of period	$ 186
Weighted average years remaining, outstanding	2 years	2 years 4 months 24 days
Weighted average years remaining, exercisable, end of period	1 year 7 months 6 days