Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 76,016	$ 82,759
Short-term investments	231,243	216,331
Accounts receivable	48,241	38,037
Inventories	111,897	99,281
Other current assets	16,707	12,762
Total current assets	484,104	449,170
Property and equipment, net	153,770	144,636
Long-term investments	5,250	5,256
Goodwill	6,571	6,571
Acquisition-related intangible assets, net	701	951
Deferred tax assets, net	15,840	15,917
Other long-term assets	31,531	30,068
Total assets	697,767	652,569
Current liabilities:
Accounts payable	27,511	22,813
Accrued compensation and related benefits	13,060	15,597
Accrued liabilities	32,730	27,507
Total current liabilities	73,301	65,917
Income tax liabilities	31,900	31,621
Other long-term liabilities	34,260	33,024
Total liabilities	139,461	130,562
Commitments and contingencies
Stockholders' equity:
Common stock and additional paid-in capital, $0.001 par value; shares authorized: 150,000; shares issued and outstanding: 42,145 and 41,614 as of March 31, 2018 and December 31, 2017, respectively	401,007	376,586
Retained earnings	152,257	143,608
Accumulated other comprehensive income	5,042	1,813
Total stockholders’ equity	558,306	522,007
Total liabilities and stockholders’ equity	$ 697,767	$ 652,569