Statement of Financial Position - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets, Current [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 37,859	$ 44,554
Marketable Securities, Current	87,872	116,924
Accounts Receivable, Net, Current	64,912	55,492
Inventory, Net	65,485	71,490
Income Taxes Receivable	2,389	0
Prepaid Expense and Other Assets	4,113	8,137
Assets, Current	262,630	296,597
Property, Plant and Equipment, Net	11,858	12,346
Goodwill	22,495	22,495
Intangible Assets, Net (Excluding Goodwill)	10,273	12,593
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	30,850	34,973
Other Assets, Noncurrent	593	559
Assets	338,699	379,563
Liabilities, Current [Abstract]
Accounts Payable, Current	10,245	9,094
Accrued Liabilities, Current [Abstract]
Employee-related Liabilities, Current	8,968	10,142
Accrued Royalties	493	336
Product Warranty Accrual, Current	1,788	1,894
Convertible Debt, Current	0	57,846
Taxes Payable, Current	0	1,163
Deferred Revenue	7,329	6,441
Other Liabilities, Current	7,139	12,415
Liabilities, Current	35,962	99,331
Convertible Debt, Noncurrent		57,846
Other Liabilities, Noncurrent	9,002	9,554
Liabilities	44,964	108,885
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock issued and outstanding	0	0
Common Stock, Value, Issued	31	31
Additional Paid in Capital, Common Stock	381,189	394,928
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2,779)	(2,623)
Retained Earnings (Accumulated Deficit)	(84,706)	(121,658)
Stockholders' Equity Attributable to Parent	293,735	270,678
Liabilities and Equity	$ 338,699	$ 379,563