Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 83,075	$ 82,759
Short-term investments	230,428	216,331
Accounts receivable	53,460	38,037
Inventories	128,909	99,281
Other current assets	13,974	12,762
Total current assets	509,846	449,170
Property and equipment, net	150,658	144,636
Long-term investments	5,247	5,256
Goodwill	6,571	6,571
Acquisition-related intangible assets, net	504	951
Deferred tax assets, net	15,791	15,917
Other long-term assets	31,335	30,068
Total assets	719,952	652,569
Current liabilities:
Accounts payable	26,689	22,813
Accrued compensation and related benefits	15,604	15,597
Accrued liabilities	33,033	27,507
Total current liabilities	75,326	65,917
Income tax liabilities	30,735	31,621
Other long-term liabilities	34,871	33,024
Total liabilities	140,932	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: 42,285 and 41,614 as of June 30, 2018 and December 31, 2017, respectively	417,866	376,586
Retained earnings	162,859	143,608
Accumulated other comprehensive income (loss)	(1,705)	1,813
Total stockholders’ equity	579,020	522,007
Total liabilities and stockholders’ equity	$ 719,952	$ 652,569