Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 84,550	$ 73,439
Short-term investments	34,396	46,919
Accounts receivable, less allowance for doubtful accounts of $19 and $136 at December 31, 2015 and 2014, respectively	71,917	88,502
Other receivables	19,321	33,295
Inventory, net	91,533	85,948
Prepaid expenses and other current assets	10,145	5,891
Deferred tax assets, net	18,924	17,095
Total Current Assets	330,786	351,089
Property, plant and equipment, net	73,233	74,828
Deferred tax assets, net	18,091	17,694
Goodwill	3,492	3,492
Other assets	9,276	10,942
Long-term investments	198,026	280,649
Total Assets	632,904	738,694
Current Liabilities
Accounts payable	48,668	56,414
Unearned revenue	16,615	22,762
Accrued expenses	12,108	11,077
Accrued wages and benefits	12,857	13,855
Income tax payable, net	2,395	14,901
Total Current Liabilities	92,643	119,009
Non-current unearned revenue	7,965	10,948
Other non-current liabilities	24,236	30,924
Bonds payable	27,900	28,800
Total Liabilities	$ 152,744	$ 189,681
Commitments and contingencies (see Note 12)
Stockholders' Equity
Common stock, par value $0.01 per share; 200,000 shares authorized; 79,652 shares issued and 49,558 shares outstanding at December 31, 2015 and 79,652 shares issued and 53,431 shares outstanding at December 31, 2014	$ 797	$ 797
Additional paid-in capital	246,879	241,829
Accumulated other comprehensive loss	(8,969)	(75)
Retained earnings	906,772	907,751
Less treasury stock at cost: 30,094 and 26,221 shares at December 31, 2015 and 2014, respectively	(665,319)	(601,289)
Total Stockholders' Equity	480,160	549,013
Total Liabilities and Stockholders' Equity	$ 632,904	$ 738,694