Stock Option Plans and Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

Stock Option Plans and Share-Based Compensation [Abstract]

PSU % eligible vesting vs Total Shareholder Return - Second year [Table Text Block]

The following table shows the percent of PSUs granted in 2012 eligible for further time-based vesting based on our percentile placement:

Percentile Placement of Our Total Shareholder Return	% of PSUs Eligible for Time- Based Vesting
Below the 35th percentile	—%
At least the 35th percentile, but below the 50th percentile	50%
At least the 50th percentile	100%

Schedule of Stock Options Roll Forward [Table Text Block]

A summary of option activity under the 2009 Plan for the three months ended March 31, 2014 is presented below:

Options:	Number of Shares		Weighted-Average Exercise Price
	(in thousands)
Outstanding at December 31, 2013	3,143		$	15.82
Granted	241		$	25.43
Exercised	(401	)	$	15.24
Forfeited	(38	)	$	16.54
Expired	(3	)	$	22.99
Outstanding at March 31, 2014	2,942		$	16.67
Vested and expected to vest at March 31, 2014	2,909		$	16.61
Exercisable at March 31, 2014	1,810		$	15.08

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

A summary of activity of both restricted stock and RSUs for the three months ended March 31, 2014 is presented below:

	Restricted Stock			Restricted Stock Units
	Number of Shares	Weighted-Average Grant Date Fair Value Per Share		Number of Shares		Weighted-Average Grant Date Fair Value Per Share
	(in thousands)			(in thousands)
Non-vested, December 31, 2013	52	$	18.43	362		$	17.15
Granted	—	$	—	97		$	25.54
Vested	—	$	—	(31	)	$	15.69
Forfeited	—	$	—	(14	)	$	15.45
Non-vested, March 31, 2014	52	$	18.43	414		$	19.27

The fair value of restricted stock is the product of the number of shares granted and the closing market price of our common stock on the grant date. Our unrecognized compensation cost related to non-vested restricted stock is approximately $7.2 million and is expected to be recognized over a weighted-average period of 2.8 years.

PSU % eligible vesting vs total Shareholder Return placement - First year [Table Text Block]

A summary of activity of the PSUs for the three months ended March 31, 2014 is presented below:

Performance-based Stock Units	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
	(in thousands)
Non-vested, December 31, 2013	225		$	13.32
Granted	132		$	16.59
Vested	(34	)	$	14.81
Forfeited	—		$	—
Non-vested, March 31, 2014	323		$	14.41

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

 The impact on our results for share-based compensation was as follows (in thousands):

	Three Months Ended March 31,
	2014		2013
Cost of product and service revenues	$	268	$	305
Research and development expenses	369		289
Selling, general and administrative expenses	2,092		2,332
Total share-based compensation expenses	$	2,729	$	2,926