Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001406666 (http://www.sec.gov/CIK)

Balance Sheet Related Disclosures [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Balance Sheet Related Disclosures [Abstract]
Accounts Receivable, net	Accounts receivable, net consisted of the following (in thousands):     December 31, 2016   December 31, 2015 Accounts receivable   $ 52,792   $ 48,319 Allowance for doubtful accounts   (518 )   (501 ) Product return reserve   (938 )   (663 ) Accounts receivable, net   $ 51,336   $ 47,155
Changes In Allowance For Doubtful Accounts And Product Reserve	The table below summarizes the changes in allowance for doubtful accounts and product return reserve for the periods indicated (in thousands):     Balance at Beginning of Year   Additions Charged to Costs or Expenses or Revenue   Deductions and Write Offs   Balance at End of Year Year Ended December 31, 2016                 Allowance for doubtful accounts   $ 501   $ 232   $ (215 )   $ 518 Product return reserve   663   3,679   (3,404 )   938 Year Ended December 31, 2015                 Allowance for doubtful accounts   $ 241   $ 405   $ (145 )   $ 501 Product return reserve   508   4,224   (4,069 )   663 Year Ended December 31, 2014                 Allowance for doubtful accounts   $ 358   $ 154   $ (271 )   $ 241 Product return reserve   764   4,805   (5,061 )   508
Inventory	Inventory consisted of the following (in thousands):     December 31, 2016   December 31, 2015 Raw materials   $ 1,827   $ 2,209 Finished goods   42,718   45,458 Total inventory   $ 44,545   $ 47,667
Property and Equipment, net	Property and equipment, net consisted of the following (in thousands):     December 31, 2016   December 31, 2015 Test equipment   $ 43,580   $ 39,035 Computer equipment and purchased software   30,306   27,736 Furniture and fixtures   2,831   1,833 Leasehold improvements   6,898   6,554 Total   83,615   75,158 Accumulated depreciation and amortization   (65,631 )   (58,009 ) Property and equipment, net   $ 17,984   $ 17,149
Accrued Liabilities	Accrued liabilities consisted of the following (in thousands):     December 31, 2016   December 31, 2015 Advance customer payments   $ 20,726   $ 1,094 Accrued compensation and related benefits   19,541   13,809 Accrued warranty and retrofit   12,214   9,564 Accrued professional and consulting fees   8,205   2,813 Accrued customer rebates   1,931   784 Accrued excess and obsolete inventory at contract manufacturers   1,327   1,011 Accrued freight   1,198   486 Accrued insurance   804   — Accrued non-income related taxes   699   905 Accrued business travel expenses   463   580 Accrued rent   421   381 Accrued hosting services   240   466 Income taxes payable   231   322 Accrued other   1,715   3,297 Total accrued liabilities   $ 69,715   $ 35,512
Deferred Revenue	Deferred revenue consisted of the following (in thousands):     December 31, 2016   December 31, 2015 Current:         Product and services   $ 24,472   $ 8,937 Extended warranty   3,382   3,187     27,854   12,124 Non-current:         Product and services   22   58 Extended warranty   20,215   19,511     20,237   19,569 Total deferred revenue   $ 48,091   $ 31,693