Common Stock Equity Incentive Plan (Stock Option Activity) (Details) - Stock Option - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Number of options
Outstanding at beginning of period (in shares)	596,385
Options granted (in shares)	0
Options exercised (in shares)	0
Options forfeited (in shares)	(1,633)
Options expired (in shares)	(16,488)
Outstanding at end of period (in shares)	578,264	596,385
Weighted average exercise price
Outstanding, weighted average exercise price at beginning of period (in dollars per share)	$ 29.68
Granted, weighted average exercise price (in dollars per share)	0
Exercised, weighted average exercise price (in dollars per share)	0
Forfeited, weighted average exercise price (in dollars per share)	22.17
Expired, weighted average exercise price (in dollars per share)	0.68
Outstanding, weighted average exercise price at end of period (in dollars per share)	$ 31.64	$ 29.68
Options exercisable at end of period (in shares)	401,857
Exercisable, weighted average exercise price (in dollars per share)	$ 38.30
Outstanding, weighted average remaining contractual term, in years	7 years 9 months 18 days	5 years
Exercisable, weighted average remaining contractual term, in years	8 years