Stockholders' Equity (Options) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	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)	1,880,846	1,953,334	2,179,787	1,880,846
Number of options
Balance at the beginning of period (in shares)	1,953,334	2,179,787
Options granted (in shares)	0	0
Options exercised (in shares)	(51,451)	(147,463)
Options forfeited (in shares)	(21,037)	(78,990)
Balance at the end of the period (in shares)	1,880,846	1,953,334	2,179,787
Number of options vested and expected to vest (in shares)				1,880,846
Number of options vested and exercisable (in shares)				1,794,439
Weighted average exercise price
Balance at the beginning of period (in dollars per share)	$ 7.42	$ 7.60
Options exercised (in dollars per share)	2.44	7.79
Options forfeited (in dollars per share)	19.39	11.68
Balance at the end of period (in dollars per share)	$ 7.42	$ 7.42	$ 7.60
Additional information
Weighted average remaining contractual term	5 years 5 months 23 days	6 years 3 months 18 days	7 years 3 months 7 days
Weighted average remaining contractual term, vested and exercisable	5 years 8 months 26 days
Options granted (in shares)	0	0
Weighted average grant date fair value (in dollars per share)			$ 4.54
Stock-based compensation expense	$ 600,000	$ 1,600,000	$ 2,200,000
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)				$ 0
Aggregate intrinsic value (in dollars)	$ 600,000	$ 2,000,000	$ 3,100,000
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)	360,015,000			360,015,000
Number of shares available for future grants				0
Number of options
Balance at the end of the period (in shares)	360,015,000
2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)				4,710,672,000	1,027,500,000
Number of shares available for future grants				615,460,000
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants				217,379,000
Number of shares awarded	1,294,949,000
Grant period of stock awards	10 years
Number of additional years of requisite service period	3 years
Inducement Plan | Minimum
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%
Inducement Plan | Minimum | Individual options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage	25.00%
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
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%