CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 32,649	$ 62,134
Short-term marketable securities	221,346	188,323
Accounts receivable, net of allowances for doubtful accounts of $605 and $525 in 2017 and 2016, respectively	18,697	6,528
Inventories	52,432	52,564
Prepaid expenses and other current assets	16,902	8,715
Total current assets	342,026	318,264
PROPERTY AND EQUIPMENT, net	113,202	95,296
INTANGIBLE ASSETS, net	28,324	31,502
GOODWILL	91,849	91,849
DEFERRED TAX ASSETS	19,328	11,342
OTHER ASSETS	6,809	6,157
Total assets	601,538	554,410
CURRENT LIABILITIES:
Accounts payable	30,124	29,727
Accrued payroll and related expenses	11,639	10,756
Taxes payable	1,072	729
Other accrued liabilities	3,858	2,734
Total current liabilities	46,693	43,946
LONG-TERM INCOME TAXES PAYABLE	2,805	2,639
DEFERRED TAX LIABILITIES	615	820
OTHER LIABILITIES	4,422	3,921
Total liabilities	54,535	51,326
COMMITMENTS AND CONTINGENCIES (Notes 11, 12 and 13)
STOCKHOLDERS’ EQUITY:
Common stock	29	28
Additional paid-in capital	189,259	172,875
Accumulated other comprehensive loss	(2,419)	(2,710)
Retained earnings	360,134	332,891
Total stockholders’ equity	547,003	503,084
Total liabilities and stockholders’ equity	$ 601,538	$ 554,410