Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 93,287	$ 75,104
Short-term investments	81,756	85,521
Accounts receivable, net of allowances of $7 as of March 31, 2013 and $20 as of December 31, 2012	22,669	19,383
Inventories	34,949	32,115
Deferred income tax assets, net - current	6	1
Prepaid expenses and other current assets	1,764	2,177
Total current assets	234,431	214,301
Property and equipment, net	62,871	59,412
Long-term investments	11,715	11,755
Deferred income tax assets, net - long-term	669	669
Other assets	1,105	1,025
Total assets	310,791	287,162
Current liabilities:
Accounts payable	13,256	9,859
Accrued compensation and related benefits	6,875	7,686
Accrued liabilities	7,679	5,915
Total current liabilities	27,810	23,460
Long-term liabilities	1,250
Non-current income tax liabilities	5,420	5,408
Total liabilities	34,480	28,868
Stockholders' equity:
Common stock, $0.001 par value; shares authorized: 150,000; shares issued and outstanding: 36,733 and 35,673 as of March 31, 2013 and December 31, 2012, respectively	209,316	194,079
Retained earnings	62,539	60,040
Accumulated other comprehensive income	4,456	4,175
Total stockholders’ equity	276,311	258,294
Total liabilities and stockholders’ equity	$ 310,791	$ 287,162