Stock-Based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Options
Options outstanding at beginning of period (in shares)	3,383,972	3,375,909	3,375,909
Granted (in shares)	0	0
Canceled / forfeited (in shares)	(907)	(234)
Exercised (in shares)	(8,150)
Expired (in shares)	(3,207)	(1,634)
Options outstanding at end of period (in shares)	3,371,708	3,374,041	3,383,972	3,375,909
Options exercisable at end of period (in shares)	71,708	74,041
Weighted- average exercise price
Options outstanding at beginning of period ( in dollars per share)	$ 5.32	$ 5.44	$ 5.44
Granted (in dollars per share)	0.00	0.00
Canceled / forfeited (in dollars per share)	3.62	78.08
Exercised (in dollars per share)	4.60
Expired (in dollars per share)	273.20	151.20
Options outstanding at end of period (in dollars per share)	5.06	5.34	$ 5.32	$ 5.44
Options exercisable at end of period (in dollars per share)	$ 17.68	$ 29.80
Options, Additional Disclosures
Weighted-average remaining contractual term (years), Options outstanding	7 years 9 months 2 days	8 years 9 months 2 days	8 years	9 years
Weighted-average remaining contractual term (years), Options exercisable	4 years 1 month	4 years 6 months 2 days
Aggregate intrinsic value outstanding	$ 9,769,300	$ 3,038,400	$ 11,180,800	$ 4,243,700
Aggregate intrinsic value exercisable	$ 133,300	$ 2,400