NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Income taxes (Details)	12 Months Ended
	Dec. 31, 2016
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards Expiration Period	20 years
State and Local Jurisdiction | COLORADO
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards Expiration Period	7 years
State and Local Jurisdiction | Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards Expiration Period	20 years
State and Local Jurisdiction | Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards Expiration Period	5 years