Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 70,914	$ 84,550
Short-term investments	50,867	34,396
Accounts receivable, less allowance for doubtful accounts of $19 at June 30, 2016 and December 31, 2015	89,386	71,917
Other receivables	11,676	19,321
Income tax receivable, net	2,405
Inventory, net	86,936	91,533
Prepaid expenses and other current assets	13,563	10,145
Deferred tax assets, net	18,488	18,924
Total Current Assets	344,235	330,786
Property, plant and equipment, net	74,115	73,233
Deferred tax assets, net	19,127	18,091
Goodwill	3,492	3,492
Other assets	9,340	9,276
Long-term investments	186,249	198,026
Total Assets	636,558	632,904
Current Liabilities
Accounts payable	59,211	48,668
Unearned revenue	15,982	16,615
Accrued expenses	12,126	12,108
Accrued wages and benefits	15,702	12,857
Income tax payable, net		2,395
Total Current Liabilities	103,021	92,643
Non-current unearned revenue	6,437	7,965
Other non-current liabilities	25,476	24,236
Bonds payable	27,900	27,900
Total Liabilities	162,834	152,744
Commitments and contingencies (see Note 13)
Stockholders’ Equity
Common stock, par value $0.01 per share; 200,000 shares authorized; 79,652 shares issued and 48,712 shares outstanding at June 30, 2016 and 79,652 shares issued and 49,558 shares outstanding at December 31, 2015	797	797
Additional paid-in capital	249,851	246,879
Accumulated other comprehensive loss	(8,695)	(8,969)
Retained earnings	912,536	906,772
Less treasury stock at cost: 30,940 and 30,094 shares at June 30, 2016 and December 31, 2015, respectively	(680,765)	(665,319)
Total Stockholders’ Equity	473,724	480,160
Total Liabilities and Stockholders’ Equity	$ 636,558	$ 632,904