Stockholders' Equity (Options) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 03, 2014	Apr. 30, 2007
Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Balance at the end of the period (in shares)	1,703,963	1,959,501	1,880,846
Number of options
Balance at the beginning of period (in shares)	1,959,501	1,880,846
Options granted (in shares)	0	600,000	0
Options exercised (in shares)	(72,726)	(9,817)
Options forfeited (in shares)	(182,812)	(511,528)
Balance at the end of the period (in shares)	1,703,963	1,959,501	1,880,846
Number of options vested and expected to vest (in shares)	1,703,963
Number of options vested and exercisable (in shares)	1,266,428
Weighted average exercise price
Balance at the beginning of period (in dollars per share)	$ 4.79	$ 7.42
Options granted (in dollars per share)		3.58
Options exercised (in dollars per share)	3.99	2.89
Options forfeited (in dollars per share)	5.49	8.87
Balance at the end of period (in dollars per share)	$ 4.75	$ 4.79	$ 7.42
Additional information
Weighted average remaining contractual term	5 years 4 months 28 days	5 years 11 months 1 day	5 years 5 months 23 days
Weighted average remaining contractual term, vested and exercisable	7 years 3 months 7 days
Options granted (in shares)	0	600,000	0
Weighted average grant date fair value (in dollars per share)		$ 3.58
Stock-based compensation expense	$ 500,000	$ 100,000	$ 600,000
Number of years from the date of grant for tax benefits	2 years
Number of years from the date of exercise for tax benefits	1 year
Unrecognized compensation costs (in dollars)	$ 1,500,000
Aggregate intrinsic value (in dollars)	$ 208,000	$ 14,000	$ 600,000
Stock Option
Assumptions used to estimate the fair value of stock options
Expected term (in years)		6 years 6 months
Expected volatility		82.65%
Risk-free interest rate		0.27%
2007 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)					1,690,448,000
Balance at the end of the period (in shares)	114,120,000
Number of shares available for future grants	0
Number of options
Balance at the end of the period (in shares)	114,120,000
2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	8,717,856,000			1,027,500,000
Number of shares available for future grants	2,190,272,000
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants	606,112,000
Number of shares awarded	1,983,411,000
Grant period of stock awards	10 years
Number of additional years of requisite service period		3 years
Vesting period	1 year
Inducement Plan | On the first anniversary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage	25.00%
Inducement Plan | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant	100.00%
Percentage of possible payouts of the target award	0.00%
Inducement Plan | Minimum [Member] | Individual options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage	25.00%
Inducement Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of possible payouts of the target award	100.00%
2007 Plan and 2014 Plan | Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant period of stock awards	10 years
2007 Plan and 2014 Plan | Stock options | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant	100.00%
Percentage of voting power owned by shareholder	10.00%
2007 Plan and 2014 Plan | Stock options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant	110.00%