Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 101,735	$ 75,104
Short-term investments	87,884	85,521
Accounts receivable, net of allowances of $10 as of June 30, 2013 and $20 as of December 31, 2012	20,319	19,383
Inventories	40,268	32,115
Deferred income tax assets, net - current	15	1
Prepaid expenses and other current assets	1,731	2,177
Total current assets	251,952	214,301
Property and equipment, net	67,281	59,412
Long-term investments	11,698	11,755
Deferred income tax assets, net - long-term	669	669
Other assets	994	1,025
Total assets	332,594	287,162
Current liabilities:
Accounts payable	14,954	9,859
Accrued compensation and related benefits	10,085	7,686
Accrued liabilities	7,574	5,915
Total current liabilities	32,613	23,460
Long-term liabilities	1,000
Non-current income tax liabilities	5,019	5,408
Total liabilities	38,632	28,868
Stockholders' equity:
Common stock, $0.001 par value; shares authorized: 150,000; shares issued and outstanding: 37,336 and 35,673 as of June 30, 2013 and December 31, 2012, respectively	220,648	194,079
Retained earnings	68,029	60,040
Accumulated other comprehensive income	5,285	4,175
Total stockholders’ equity	293,962	258,294
Total liabilities and stockholders’ equity	$ 332,594	$ 287,162