Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues:
Product revenues	$ 57,185	$ 50,493	$ 115,088	$ 99,951
Contract revenues	446	353	1,010	705
Total revenues	57,631	50,846	116,098	100,656
Operating expenses:
Cost of product revenues	9,013	8,226	18,340	17,285
Research and development	11,579	9,879	23,508	19,971
Selling and marketing	23,765	20,529	48,131	41,064
General and administrative	11,436	9,852	23,411	20,208
Total operating expenses	55,793	48,486	113,390	98,528
Income from operations	1,838	2,360	2,708	2,128
Interest income	74	75	149	140
Other income (expense), net	(73)	(28)	(145)	(78)
Income before income taxes	1,839	2,407	2,712	2,190
Income tax expense	38	59	135	128
Net income	$ 1,801	$ 2,348	$ 2,577	$ 2,062
Basic net income per share (in dollars per share)	$ 0.06	$ 0.08	$ 0.09	$ 0.07
Diluted net income per share (in dollars per share)	$ 0.06	$ 0.08	$ 0.08	$ 0.07
Shares used in computing basic net income per share (in shares)	30,204	29,332	30,057	29,219
Shares used in computing diluted net income per share (in shares)	32,064	30,870	31,835	30,591