Quarterly report pursuant to Section 13 or 15(d)

Stock Plans (Tables)

Stock Plans (Tables)

3 Months Ended

Mar. 31, 2014

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

The following table summarizes the stock-based compensation expense recorded for awards under the stock option plans for the three month periods ended March 31, 2014 and 2013:

	Three Months Ended March 31,
(in thousands, except per share amounts)	2014		2013
Research and development	$	145	$	304
General and administrative		181		201

Total stock-based compensation expenses	$	326	$	505

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

We use the Black-Scholes-Merton option-pricing model with the following assumptions to estimate the stock-based compensation expense for the three month period ended March 31, 2014 and 2013:

	Three Months Ended March 31,
	2014			2013
Weighted-average risk-free interest rate		2.0	%		0.64	%
Expected dividend payments		—			—
Expected holding period (years)¹		6.5			4.4
Weighted-average volatility factor²		1.66			1.83
Estimated forfeiture rates for options granted to management³		31	%		23	%
Estimated forfeiture rates for options granted to non-management³		31	%		41	%

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(1)	Expected holding periods are based on the simplified method provided in Staff Accounting Bulletin No. 107 for “plain vanilla options.”
(2)	Weighted average volatility is based on the historical volatility of our common stock.
(3)	Estimated forfeiture rates are based on historical data.

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

The following table summarizes option activity for the three month period ended March 31, 2014:

(in thousands, except per share amounts)	Options		Weighted Average Exercise Price		Weighted Average Remaining Option Term		Aggregate Intrinsic Value
Outstanding at January 1, 2014		6,732	$	1.31		5.75	$	—
Granted		275		0.66
Exercised		—		—
Expired or cancelled		(60)		3.69
Forfeited		(2)		4.06

Outstanding at March 31, 2014		6,945	$	1.27		5.57	$	3

Exercisable at March 31, 2014		6,869	$	1.27		5.52	$	2

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

The following table summarizes restricted stock activity for the three month period ended March 31, 2014:

(in thousands, except per share amounts)	Restricted Stock		Weighted Average Exercise Price		Weighted Average Remaining Term		Aggregate Intrinsic Value
Outstanding at January 1, 2014		—	$	—		—	$	—
Granted		617		—
Released		(259)		—
Expired or cancelled		—		—
Forfeited		—		—

Outstanding at March 31, 2014		358	$	—		9.87	$	207

Exercisable at March 31, 2014		—	$	—		—	$	—