Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2014

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

Weighted average assumptions used to estimate fair value of stock options granted and stock purchase rights under ESPP

The weighted average assumptions used to estimate the fair value of stock purchase rights under the ESPP are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
ESPP
Volatility	44	%	57	%	46	%	58	%
Expected term (years)	1.2		1.6		1.2		1.5
Risk free interest rate	0.2	%	0.2	%	0.2	%	0.2	%
Expected dividend yield	—	%	—	%	—	%	—	%

Compensation costs included in statement of income for all stock-based compensation arrangements

The compensation cost that has been included in the statement of operations for all stock-based compensation arrangements was as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Sales, marketing and administrative expense	$	8,251	$	8,278	$	15,437	$	14,703
Research and development expense	483		449		947		791
Cost of goods sold	51		34		165		54
Total stock-based compensation expense	$	8,785	$	8,761	$	16,549	$	15,548

At June 30, 2014, there was $42.1 million of unamortized compensation expense for stock options, restricted stock units and performance-based restricted stock units to be recognized over the remaining vesting periods.