Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 135,536	$ 139,049
Marketable securities	144,784	157,642
Accounts receivable, net	21,203	12,662
Inventories	20,148	18,092
Deferred tax assets	1,758	1,162
Refundable income taxes	905	910
Prepaid expenses and other current assets	7,011	7,458
Total current assets	331,345	336,975
Restricted cash	317	317
Property, plant and equipment, net	34,376	35,132
Deferred tax assets	5,794	5,954
Other assets	4,357	4,693
Total assets	376,189	383,071
Current liabilities:
Accounts payable	15,171	9,731
Accrued liabilities	14,106	13,966
Income taxes payable	181	100
Deferred revenue	5,449	4,798
Total current liabilities	34,907	28,595
Long-term income taxes payable	4,100	4,112
Deferred rent and other liabilities	4,310	3,712
Total liabilities	43,317	36,419
Commitments and contingencies (Note 16)
Stockholders' equity:
Preferred stock, $0.001 par value: 10,000,000 shares authorized; no shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively	0	0
Common stock, $0.001 par value: 250,000,000 shares authorized; 49,610,899 and 49,268,479 shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively	51	50
Additional paid-in capital	656,356	652,024
Accumulated other comprehensive income	2,041	2,700
Accumulated deficit	(325,576)	(308,122)
Total stockholders' equity	332,872	346,652
Total liabilities and stockholders' equity	$ 376,189	$ 383,071