Stock Options and Equity-Classified Warrants, Options by Exercise Price Range (Details)	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Stock Options [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Number of Options (in shares) | shares	17,479,770
Weighted-Average Remaining Contractual Life	8 years 14 days
Weighted-Average Exercise Price (in dollars per share)	$ 2.37
Number of Options Exercisable (in shares) | shares	11,467,920
Weighted-Average Contractual Life	7 years 3 months 29 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 2.93
Warrants [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Number of Options (in shares) | shares	32,502,790
Weighted-Average Remaining Contractual Life	1 year 4 months 6 days
Weighted-Average Exercise Price (in dollars per share)	$ 0.68
Number of Options Exercisable (in shares) | shares	30,190,290
Weighted-Average Contractual Life	1 year 4 months 6 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 0.67
Range $ 0.43 - 1.50 [Member] | Stock Options [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	0.43
Range of Exercise Prices, Upper Range (in dollars per share)	$ 1.50
Number of Options (in shares) | shares	4,432,498
Weighted-Average Remaining Contractual Life	9 years 11 months 12 days
Weighted-Average Exercise Price (in dollars per share)	$ 0.44
Number of Options Exercisable (in shares) | shares	1,086,696
Weighted-Average Contractual Life	9 years 11 months 12 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 0.45
Range $ 0.43 - 1.50 [Member] | Warrants [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	0.43
Range of Exercise Prices, Upper Range (in dollars per share)	$ 1.50
Number of Options (in shares) | shares	31,015,071
Weighted-Average Remaining Contractual Life	1 year 3 months 14 days
Weighted-Average Exercise Price (in dollars per share)	$ 0.60
Number of Options Exercisable (in shares) | shares	28,702,571
Weighted-Average Contractual Life	1 year 3 months
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 0.58
Range $ 1.51 - 2.50 [Member] | Stock Options [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	1.51
Range of Exercise Prices, Upper Range (in dollars per share)	$ 2.50
Number of Options (in shares) | shares	8,932,606
Weighted-Average Remaining Contractual Life	7 years 10 months 6 days
Weighted-Average Exercise Price (in dollars per share)	$ 2.26
Number of Options Exercisable (in shares) | shares	6,293,224
Weighted-Average Contractual Life	7 years 5 months 26 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 2.22
Range $ 1.51 - 2.50 [Member] | Warrants [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	1.51
Range of Exercise Prices, Upper Range (in dollars per share)	$ 2.50
Number of Options (in shares) | shares	1,337,719
Weighted-Average Remaining Contractual Life	2 years 8 months 8 days
Weighted-Average Exercise Price (in dollars per share)	$ 2.30
Number of Options Exercisable (in shares) | shares	1,337,719
Weighted-Average Contractual Life	2 years 3 months 18 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 2.30
Range $ 2.51 - 4.00 [Member] | Stock Options [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	2.51
Range of Exercise Prices, Upper Range (in dollars per share)	$ 4.00
Number of Options (in shares) | shares	960,670
Weighted-Average Remaining Contractual Life	7 years 1 month 17 days
Weighted-Average Exercise Price (in dollars per share)	$ 2.88
Number of Options Exercisable (in shares) | shares	934,004
Weighted-Average Contractual Life	7 years 1 month 6 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 2.87
Range $ 2.51 - 4.00 [Member] | Warrants [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	2.51
Range of Exercise Prices, Upper Range (in dollars per share)	$ 4.00
Number of Options (in shares) | shares	125,000
Weighted-Average Remaining Contractual Life	1 year 10 months 10 days
Weighted-Average Exercise Price (in dollars per share)	$ 3.75
Number of Options Exercisable (in shares) | shares	125,000
Weighted-Average Contractual Life	1 year 10 months 10 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 3.75
Range $ 4.01 - 32.55 [Member] | Stock Options [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	4.01
Range of Exercise Prices, Upper Range (in dollars per share)	$ 32.55
Number of Options (in shares) | shares	3,153,996
Weighted-Average Remaining Contractual Life	6 years 2 months 1 day
Weighted-Average Exercise Price (in dollars per share)	$ 5.24
Number of Options Exercisable (in shares) | shares	3,153,996
Weighted-Average Contractual Life	6 years 2 months 1 day
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 5.24
Range $ 4.01 - 32.55 [Member] | Warrants [Member]
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)	4.01
Range of Exercise Prices, Upper Range (in dollars per share)	$ 32.55
Number of Options (in shares) | shares	25,000
Weighted-Average Remaining Contractual Life	7 years 2 months 16 days
Weighted-Average Exercise Price (in dollars per share)	$ 5.60
Number of Options Exercisable (in shares) | shares	25,000
Weighted-Average Contractual Life	7 years 2 months 16 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 5.60