STOCKHOLDERS' EQUITY - STOCK OPTIONS OUTSTANDING (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
$1.10 - $1.51
Exercise Price Range
Exercise price, low end of range (in dollars per share)	$ 1.10
Exercise price, high end of range (in dollars per share)	$ 1.51
Options Outstanding
Number of Shares | shares	6,003,210
Weighted Average Exercise Price Per Share (in dollars per share)	$ 1.45
Weighted Average Remaining Contractual Life (In years)	6 years 6 months 29 days
$1.55 - $4.34
Exercise Price Range
Exercise price, low end of range (in dollars per share)	$ 1.55
Exercise price, high end of range (in dollars per share)	$ 4.34
Options Outstanding
Number of Shares | shares	5,412,577
Weighted Average Exercise Price Per Share (in dollars per share)	$ 3.21
Weighted Average Remaining Contractual Life (In years)	7 years 7 months 17 days
$4.42 - $5.09
Exercise Price Range
Exercise price, low end of range (in dollars per share)	$ 4.42
Exercise price, high end of range (in dollars per share)	$ 5.09
Options Outstanding
Number of Shares | shares	4,744,005
Weighted Average Exercise Price Per Share (in dollars per share)	$ 4.99
Weighted Average Remaining Contractual Life (In years)	7 years 4 months 28 days
$5.14 - $9.32
Exercise Price Range
Exercise price, low end of range (in dollars per share)	$ 5.14
Exercise price, high end of range (in dollars per share)	$ 9.32
Options Outstanding
Number of Shares | shares	1,045,891
Weighted Average Exercise Price Per Share (in dollars per share)	$ 6.47
Weighted Average Remaining Contractual Life (In years)	2 years 5 months 12 days
$1.10 - $9.32
Exercise Price Range
Exercise price, low end of range (in dollars per share)	$ 1.10
Exercise price, high end of range (in dollars per share)	$ 9.32
Options Outstanding
Number of Shares | shares	17,205,683
Weighted Average Exercise Price Per Share (in dollars per share)	$ 3.29
Weighted Average Remaining Contractual Life (In years)	6 years 10 months 21 days