Stockholders' Equity, Equity Incentive Plans and Warrants (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-based compensation expense

The following table summarizes share-based compensation expense for the years ended December 31, (in thousands):

	2011		2012		2013
Cost of goods sold	$	828	$	617	$	334
Sales and marketing	540		419		274
Research and development	2,200		1,705		1,054
General and administrative	1,548		1,024		1,028
Share-based compensation expense before taxes	5,116		3,765		2,690
Related deferred income tax benefits	—		—		—
Share-based compensation expense	$	5,116	$	3,765	$	2,690
Share-based compensation expense is derived from:
Stock options	$	1,434	$	1,508	$	1,924
Restricted stock awards	2,303		1,958		489
Stock bonus plan	1,005		—		—
2000 ESPP	374		299		277
Total	$	5,116	$	3,765	$	2,690

Summary of stock option activity

A summary of stock option activity is as follows:

	Number of shares		Weighted average exercise price		Weighted average remaining contractual term (in years)	Aggregate intrinsic value
Outstanding at January 1, 2013	8,952,129		$	2.93
Granted	2,331,500		1.57
Exercised	(210,551	)	1.53
Forfeited	(268,985	)	1.47
Expired	(953,595	)	3.94
Outstanding at December 31, 2013	9,850,498		$	2.58	4.35	$	12,056,111
Vested and expected to vest at December 31, 2013	9,511,564		$	2.62	4.28	$	11,423,719
Exercisable at December 31, 2013	6,155,904		$	3.17	3.65	$	5,528,671

Summary of restricted stock activity

A summary of restricted stock award activity for 2013 is as follows:

	Number of shares		Weighted average grant date fair value
Outstanding at January 1, 2013	655,402		$	2.16
Granted	30,000		1.74
Vested	(567,268	)	2.22
Forfeited	(25,323	)	1.84
Outstanding and unvested at December 31, 2013	92,811		$	1.73

Schedule of valuation assumptions for equity awards

To estimate compensation expense for the years ended December 31, 2011, 2012, and 2013 we used the Black-Scholes pricing model with the following weighted-average assumptions for equity awards granted:

	EIP and NEDSOP						ESPP
	Years Ended December 31,						Years Ended December 31,
	2011		2012		2013		2011		2012		2013
Risk-free interest rate	1.84	%	1.19	%	1.07	%	0.17	%	0.12	%	0.09	%
Expected dividend yield	—	%	—	%	—	%	—	%	—	%	—	%
Volatility	85	%	81	%	82	%	70	%	64	%	63	%
Expected Term	5.4 years		5.2 years		5.3 years		0.5 years		0.5 years		0.5 years
Forfeiture Rate	0%-12.25%		0%-10.62%		0%-9.45%		—	%	—	%	—	%