Equity - Non-Option Incentive (Details)			1 Months Ended	12 Months Ended
	May 21, 2020 USD ($) employee shares	Feb. 26, 2020 USD ($) employee shares	Sep. 30, 2014 shares	Dec. 31, 2020 USD ($) employee director $ / shares shares	Dec. 31, 2019 USD ($) employee director $ / shares shares
Weighted Average Grant Date Fair Value Per Share - Non-option
Compensation expense | $				$ 859,000	$ 782,000
Modification of previously awarded KELTIP Units (Note 16) | $					$ 583,000
Sentient | 2014 Warrants
Number of Shares - Non-option
Granted during the year (in shares)			4,746,000
KELTIP Units
Weighted Average Grant Date Fair Value Per Share - Non-option
Compensation expense | $	$ 448,000
KELTIP Units | Officers
Number of Shares - Non-option
Granted during the year (in shares)	1,400,000	705,000
Weighted Average Grant Date Fair Value Per Share - Non-option
Number of employees | employee	2	2
Equity Plan | Restricted Stock
Number of Shares - Non-option
Outstanding at beginning of year (in shares)				318,003	340,001
Granted during the year (in shares)				300,000	312,000
Restrictions lifted during the year (in shares)				(394,001)	(333,998)
Outstanding at end of year (in shares)				224,002	318,003
Weighted Average Grant Date Fair Value Per Share - Non-option
Outstanding at beginning of year (in dollars per share) | $ / shares				$ 0.30	$ 0.45
Granted during the year (in dollars per share) | $ / shares				0.42	0.26
Restrictions lifted during the year (in dollars per share) | $ / shares				0.36	0.41
Outstanding at end of year (in dollars per share) | $ / shares				$ 0.36	$ 0.30
Compensation expense | $				$ 100,000
Additional compensation expense expected to be recognized | $				$ 100,000
Period for future recognition of additional compensation expense				18 months
Equity Plan | Restricted Stock | Employees
Number of Shares - Non-option
Granted during the year (in shares)				300,000	312,000
Weighted Average Grant Date Fair Value Per Share - Non-option
Compensation expense | $					$ 100,000
Number of employees | employee				7	2
Equity Plan | Restricted Stock Units (RSUs) | Employees
Number of Shares - Non-option
Restrictions lifted during the year (in shares)					(214,001)
Deferred Compensation Plan | Restricted Stock | Employees
Number of Shares - Non-option
Restrictions lifted during the year (in shares)					(229,998)
Weighted Average Grant Date Fair Value Per Share - Non-option
Number of employees | employee					5
Deferred Compensation Plan | Restricted Stock | Terminated Employees
Weighted Average Grant Date Fair Value Per Share - Non-option
Additional compensation expense | $				$ 23,000
Deferred Compensation Plan | Restricted Stock Units (RSUs)
Number of Shares - Non-option
Outstanding at beginning of year (in shares)				2,830,038	2,230,038
Granted during the year (in shares)				780,000	600,000
Outstanding at end of year (in shares)				3,610,038	2,830,038
Weighted Average Grant Date Fair Value Per Share - Non-option
Outstanding at beginning of year (in dollars per share) | $ / shares				$ 0.78	$ 0.93
Granted during the year (in dollars per share) | $ / shares				0.40	0.24
Outstanding at end of year (in dollars per share) | $ / shares				$ 0.70	$ 0.78
Compensation expense | $				$ 300,000	$ 200,000
Additional compensation expense expected to be recognized | $				$ 100,000
Period for future recognition of additional compensation expense					6 months
Number of unrestricted shares Director to receive for vested RSU upon termination from board				1
Number of board members | director				6	6
Deferred Compensation Plan | Restricted Stock Units (RSUs) | Director
Number of Shares - Non-option
Granted during the year (in shares)				300,000
Weighted Average Grant Date Fair Value Per Share - Non-option
Compensation expense | $				$ 120,000
Deferred Compensation Plan | Restricted Stock Units (RSUs) | Board Members [Member]
Number of Shares - Non-option
Granted during the year (in shares)				80,000	100,000
KELTIP
Number of Shares - Non-option
Outstanding at beginning of year (in shares)				2,325,000
Outstanding at end of year (in shares)				3,725,000	2,325,000
KELTIP | KELTIP Units | Officers
Weighted Average Grant Date Fair Value Per Share - Non-option
Compensation expense | $		$ 254,000
Additional compensation expense | $		227,000
Modification of previously awarded KELTIP Units (Note 16) | $		$ 583,000
Restricted Stock | Equity Plan | Employees
Weighted Average Grant Date Fair Value Per Share - Non-option
Number of employees | employee				7
Restricted Stock | Deferred Compensation Plan | Terminated Employees
Number of Shares - Non-option
Restrictions lifted during the year (in shares)				(80,000)
Vesting immediately | Equity Plan | Restricted Stock
Weighted Average Grant Date Fair Value Per Share - Non-option
Percentage of awards which will vest on each of the first, second and third anniversaries of the grant date					33.33%
Vesting immediately | Equity Plan | Restricted Stock | Employees
Number of Shares - Non-option
Granted during the year (in shares)					104,000
Vest on first anniversary | Equity Plan | Restricted Stock
Weighted Average Grant Date Fair Value Per Share - Non-option
Percentage of awards which will vest on each of the first, second and third anniversaries of the grant date					33.33%
Vest on first anniversary | Equity Plan | Restricted Stock | Employees
Weighted Average Grant Date Fair Value Per Share - Non-option
Percentage of awards which will vest on each of the first, second and third anniversaries of the grant date					33.33%
Vest on second anniversary | Equity Plan | Restricted Stock
Weighted Average Grant Date Fair Value Per Share - Non-option
Percentage of awards which will vest on each of the first, second and third anniversaries of the grant date					33.34%
Vest on second anniversary | Equity Plan | Restricted Stock | Employees
Weighted Average Grant Date Fair Value Per Share - Non-option
Percentage of awards which will vest on each of the first, second and third anniversaries of the grant date					33.34%