Condensed Consolidated Balance Sheets (USD $)	Jun. 30, 2013		Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 502,721,765		$ 389,678,664
Short-term investments	92,516,252		60,802,856
Accounts receivable, net	120,187,023		109,579,693
Inventories	116,001,970		159,930,266
Prepaid expenses and other	24,044,587		24,671,561
Total current assets	855,471,597		744,663,040
PLANT AND EQUIPMENT—NET	345,931,734		349,938,172
OTHER ASSETS
Long-term investments	136,977,928		141,834,034
Patents and other assets, net	27,895,756		29,256,089
Total other assets	164,873,684		171,090,123
Total assets	1,366,277,015		1,265,691,335
CURRENT LIABILITIES
Accounts payable	43,789,630		43,200,002
Accrued liabilities	60,094,081		44,757,440
Total current liabilities	103,883,711		87,957,442
DEFERRED INCOME TAXES	55,383,634		56,773,337
SHAREHOLDERS’ INVESTMENT
Common stock	8,655,585		8,584,581
Additional paid-in capital	444,299,603		418,766,010
Retained earnings	733,268,066		676,039,254
Accumulated other comprehensive income	20,786,416	[1]	17,570,711
Total shareholders’ investment	1,207,009,670		1,120,960,556
Total liabilities and shareholders’ investment	$ 1,366,277,015		$ 1,265,691,335

[1] All amounts are shown net of tax. Amounts in parentheses indicate debits.