Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 89,002	$ 96,671
Marketable securities	84,649	70,888
Accounts receivable, less allowance of $315 as of March 31, 2012 and $262 as of December 31, 2011	38,665	41,036
Inventories	53,154	49,501
Prepaid expenses and other current assets	6,668	5,005
Total current assets	272,138	263,101
Property, plant and equipment, net	11,077	12,530
Goodwill	4,492	4,492
Identifiable intangible assets, net	7,398	7,814
Other assets	17,980	17,974
Total assets	313,085	305,911
Current liabilities:
Accounts payable and accrued liabilities	17,172	12,201
Other current liabilities	15,143	16,656
Total current liabilities	32,315	28,857
Convertible senior notes	47,129	46,524
Other non-current liabilities	8,693	8,752
Total liabilities	88,137	84,133
Stockholders' equity:
Common stock	32	32
Additional paid-in capital	406,650	405,505
Accumulated other comprehensive loss	(1,299)	(1,462)
Accumulated deficit	(180,435)	(182,297)
Total stockholders' equity	224,948	221,778
Total liabilities and stockholders' equity	$ 313,085	$ 305,911