CAPITAL STOCK, Employee Stock Purchase Plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan Description	The Company’s Second Amended and Restated 1996 Employee Stock Purchase Plan (the “ESPP”) offers the Company’s shares for purchase at a price equal to 85% of the closing price on the applicable offering period termination date. Shares issued under the ESPP are considered compensatory. Accordingly, the Company is required to measure fair value and record compensation expense for share purchase rights granted under the ESPP. In July 2015, the Board of Directors approved an amendment to the ESPP to change the subscription period from three to six months and accordingly to adjust the payroll cap to $5,000 per plan period.
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	691,701
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	117,764
Weighted-average assumptions and fair value of shares issued under the ESPP
Expected dividend yield (in hundredths)	0.00%	0.00%	0.00%
Risk-free interest rate (in hundredths)	0.83%	0.40%	0.03%
Expected volatility (in hundredths)	62.00%	69.00%	37.00%
Expected life (in years)	179 days	179 days	88 days
Weighted-average fair value of shares issued (in dollars per share)	$ 0.86	$ 1.20	$ 2.15
Shares issued under the ESPP (in shares)	96,507	129,342	98,300
Average price of shares issued (in dollars per share)	$ 4.53	$ 4.35	$ 10.17