Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 63,008	$ 67,988
Short-term investments	188,893	201,742
Accounts receivable, net of allowance for doubtful accounts of $498 and $498 at December 31, 2012 and 2011, respectively	28,108	44,217
Inventories	65,398	51,859
Prepaid expenses and other current assets	3,862	5,774
Total current assets	349,269	371,580
Property, Plant, and Equipment,net	17,280	20,926
Intangible Assets, Net (Excluding Goodwill)	12,288	13,995
Other assets	10,359	11,017
Total assets	389,196	417,518
Liabilities and Stockholders' Equity
Notes payable	5,120	5,120
Accounts payable	12,080	12,086
Accrued expenses	12,146	11,302
Deferred product and services income	4,499	8,638
Total current liabilities	33,845	37,146
Other liabilities	$ 13,474	$ 15,252
Commitments and contingencies
Stockholders' Equity:
Preferred Stock, $0.001 par value: 2,000,000 shares authorized; none issued	$ 0	$ 0
Common stock, $0.001 par value: 80,000,000 shares authorized; 30,606,577 and 30,230,075 shares issued at December 31, 2015 and 2014, respectively; and 26,522,276 and 27,395,774outstanding at December 31, 2015 and 2014, respectively	30	30
Additional paid-in capital	366,629	353,366
Treasury stock: 4,084,301 and 2,834,301 shares at December 31, 2015 and 2014, respectively	(67,185)	(45,747)
Accumulated other comprehensive income (loss)	(1,199)	(1,259)
Retained Earnings (Accumulated deficit)	43,602	58,730
Total stockholders' equity	341,877	365,120
Total liabilities and stockholders' equity	$ 389,196	$ 417,518