Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Product revenues	$ 63,691	$ 57,185	$ 126,400	$ 115,088
Contract revenues		446	385	1,010
Total revenues	63,691	57,631	126,785	116,098
Operating expenses:
Cost of product revenues	10,757	9,013	20,503	18,340
Research and development	13,800	11,579	27,463	23,508
Selling and marketing	28,135	23,765	55,574	48,131
General and administrative	13,910	11,436	27,045	23,411
Total operating expenses	66,602	55,793	130,585	113,390
Income (loss) from operations	(2,911)	1,838	(3,800)	2,708
Interest income	57	74	122	149
Other income (expense), net	(85)	(73)	(91)	(145)
Income (loss) before income taxes	(2,939)	1,839	(3,769)	2,712
Income tax expense	55	38	108	135
Net income (loss)	$ (2,994)	$ 1,801	$ (3,877)	$ 2,577
Basic net income (loss) per share (in dollars per share)	$ (0.10)	$ 0.06	$ (0.13)	$ 0.09
Diluted net income (loss) per share (in dollars per share)	$ (0.10)	$ 0.06	$ (0.13)	$ 0.08
Shares used in computing basic net income per share (in shares)	30,464	30,204	30,317	30,057
Shares used in computing diluted net income per share (in shares)	30,464	32,064	30,317	31,835