Share-based compensation (Tables)

12 Months Ended

Dec. 31, 2017

Summary Of Significant Accounting Policies Share-based Compensation Tables

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The following table summarizes the weighted-average valuation assumptions and weighted-average grant date fair value of options granted during the periods shown below:

		Year Ended December 31,
Assumptions (weighted-average)		2017		2016		2015
Volatility		79%		84%		98%
Expected term (in years)		4.0		4.0		4.0
Risk-free rate		1.6%		1.2%		1.3%
Expected dividends		0.0%		0.0%		0.0%
Pre-vest forfeiture rate		8.5%		8.5%		8.5%
Grant date fair value of options granted	$	1.03	$	1.12	$	2.20

Options activity and positions

The following table summarizes activity and positions with respect to options for the periods shown below (in thousands):

				Weighted-average
				remaining		Aggregate
			Weighted-average	contractual		intrinsic
Options	Shares		exercise price	term (in years)		value
Outstanding as of January 1, 2015	2,427	$	6.72	7.4	$	18,700
Granted	849		3.23	-		-
Exercised	(23)		1.88	-		-
Forfeited or expired	(107)		13.98	-		-
Outstanding as of December 31, 2015	3,146		5.56	7.3		1,613
Granted	1,167		1.83	-		-
Exercised	(3)		1.77	-		-
Forfeited or expired	(307)		12.58	-		-
Outstanding as of December 31, 2016	4,003		3.94	7.3		4
Granted	1,724		1.76	-		-
Exercised	(46)		1.87	-		-
Forfeited or expired	(647)		6.09	-		-
Outstanding as of December 31, 2017	5,034	$	2.94	6.6	$	53
Vested and expected to vest as of December 31, 2017	4,729	$	3.00	6.4	$	49
Exercisable as of December 31, 2017	2,555	$	3.90	4.5	$	25