Enphase Energy (ENPH) 10-K 4 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 28, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'Enphase Energy, Inc.	'	'
Entity Central Index Key	'0001463101	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Amendment Flag	'false	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Non-accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	42,236,859	'
Entity Well-Known Seasoned Issuer	'No	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$113.10

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$38,190	$45,294
Accounts receivable, net of allowances of $2,000 and $1,177	32,084	27,743
Inventory	16,580	19,843
Prepaid expenses and other	3,655	2,118
Total current assets	90,509	94,998
Property and equipment, net	24,853	25,541
Other assets	1,307	1,752
Total assets	116,669	122,291
Current liabilities:	'	'
Accounts payable	7,363	11,272
Accrued liabilities	19,722	19,266
Deferred revenues	2,773	933
Current portion of term loans	3,507	2,384
Total current liabilities	33,365	33,855
Long-term liabilities:	'	'
Deferred revenues	11,284	7,537
Warranty obligations	25,490	15,260
Other liabilities	1,154	307
Term loans	5,170	8,677
Total long-term liabilities	43,098	31,781
Total liabilities	76,463	65,636
Commitments and contingencies	'	'
Stockholders’ equity:	'	'
Preferred stock, $0.00001 par value, 10,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.00001 par value, 100,000 shares authorized; 42,123 and 40,856 shares issued and outstanding at December 31, 2013 and 2012, respectively	0	0
Additional paid-in capital	192,916	183,629
Accumulated deficit	-152,939	-127,026
Accumulated other comprehensive income	229	52
Total stockholders’ equity	40,206	56,655
Total liabilities and stockholders’ equity	$116,669	$122,291

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Allowances, accounts receivable	$2,000	$1,177
Preferred stock, par value (usd per share)	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (usd per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	42,123,000	40,856,000
Common stock, shares outstanding	42,123,000	40,856,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net revenues	$232,846	$216,678	$149,523
Cost of revenues	165,430	161,390	120,454
Gross profit	67,416	55,288	29,069
Operating expenses:	'	'	'
Research and development	34,524	35,601	25,099
Sales and marketing	31,080	25,973	17,454
General and administrative	23,970	24,875	15,228
Total operating expenses	89,574	86,449	57,781
Loss from operations	-22,158	-31,161	-28,712
Other income (expense), net:	'	'	'
Interest expense	-2,055	-6,436	-3,006
Other income (expense)	-837	30	-572
Total other expense, net	-2,892	-6,406	-3,578
Loss before income taxes	-25,050	-37,567	-32,290
Provision for income taxes	-863	-651	0
Net loss attributable to common stockholders	($25,913)	($38,218)	($32,290)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	($0.62)	($1.24)	($25.73)
Shares used in computing net loss per share attributable to common stockholders, basic and diluted	41,647	30,740	1,255

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net loss attributable to common stockholders	($25,913)	($38,218)	($32,290)
Other comprehensive income (loss):	'	'	'
Foreign currency translation adjustments	177	-31	83
Other comprehensive income (loss):	177	-31	83
Comprehensive loss attributable to common stockholders	($25,736)	($38,249)	($32,207)

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
In Thousands, except Share data, unless otherwise specified
BALANCE at Dec. 31, 2010	$38,481	$93,596	$0	$1,403	($56,518)	$0
BALANCE (in shares) at Dec. 31, 2010	'	22,221,000	843,000	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Private placement of common stock at $5.27 per share	1,858	'	0	1,858	'	'
Private placement of common stock at $5.27 per share (in shares)	'	'	353,000	'	'	'
Exercise of stock options	190	'	0	190	'	'
Exercise of stock options (in shares)	502,000	'	502,000	'	'	'
Stock-based compensation	2,120	'	'	2,120	'	'
Fair value of warrants and common stock issued in connection with convertible notes	2,312	'	'	2,312	'	'
Fair value of beneficial conversion feature upon issuance of convertible notes	1,165	'	'	1,165	'	'
Fair value of beneficial conversion feature from accrued paid-in-kind interest of convertible notes	55	'	'	55	'	'
Issuance of common stock upon exercise of warrants	0	'	'	'	'	'
Net loss	-32,290	'	'	'	-32,290	'
Foreign currency translation adjustment	83	'	'	'	'	83
BALANCE at Dec. 31, 2011	13,974	93,596	0	9,103	-88,808	83
BALANCE (in shares) at Dec. 31, 2011	'	22,221,000	1,698,000	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Exercise of stock options (in shares)	59,000	'	'	'	'	'
Stock-based compensation	4,766	'	'	4,766	'	'
Common stock issued upon initial public offering (“IPO”), net of offering costs	53,826	'	0	53,826	'	'
Common stock issued upon initial public offering (“IPO”), net of offering costs (in shares)	'	'	10,315,000	'	'	'
Issuance of common stock under employee stock plans	255	'	0	255	'	'
Issuance of common stock under employee stock plans (in shares)	'	'	138,000	'	'	'
Conversion of convertible preferred stock into common stock upon IPO	0	-93,596	0	93,596	'	'
Conversion of convertible preferred stock into common stock upon IPO (in shares)	'	-22,221,000	25,171,000	'	'	'
Conversion of convertible notes and paid-in-kind interest into common stock upon IPO	21,204	'	0	21,204	'	'
Conversion of convertible notes and paid-in-kind interest into common stock upon IPO (in shares)	'	'	3,534,000	'	'	'
Reclassification of preferred stock warrant liability to APIC upon IPO	879	'	'	879	'	'
Issuance of common stock upon exercise of warrants	21,204	'	'	'	'	'
Net loss	-38,218	'	'	'	-38,218	'
Foreign currency translation adjustment	-31	'	'	'	'	-31
BALANCE at Dec. 31, 2012	56,655	0	0	183,629	-127,026	52
BALANCE (in shares) at Dec. 31, 2012	'	0	40,856,000	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Exercise of stock options (in shares)	822,000	'	'	'	'	'
Stock-based compensation	6,849	'	'	6,849	'	'
Issuance of common stock under employee stock plans	2,438	'	0	2,438	'	'
Issuance of common stock under employee stock plans (in shares)	'	'	1,255,000	'	'	'
Issuance of common stock upon exercise of warrants	0	'	0	0	'	'
Issuance of common stock upon exercise of warrants (in shares)	'	'	12,000	'	'	'
Net loss	-25,913	'	'	'	-25,913	'
Foreign currency translation adjustment	177	'	'	'	'	177
BALANCE at Dec. 31, 2013	$40,206	$0	$0	$192,916	($152,939)	$229
BALANCE (in shares) at Dec. 31, 2013	'	0	42,123,000	'	'	'

Consolidated_Statement_of_Stoc1

Consolidated Statement of Stockholders' Equity (Parenthetical) (USD $)	Apr. 04, 2012	Dec. 31, 2011
Common stock issued, price per share (usd per share)	$6	$5.27

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net loss	($25,913)	($38,218)	($32,290)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'	'
Depreciation and amortization	6,981	5,568	3,032
Provision for doubtful accounts	678	1,068	127
Net loss on disposal of assets	82	120	0
Non-cash interest expense	429	4,777	1,835
Stock-based compensation	6,849	4,766	2,120
Change in fair value of convertible preferred stock warrants	0	-520	321
Changes in operating assets and liabilities:	'	'	'
Accounts receivable	-5,019	-11,040	-9,874
Inventory	3,263	-8,615	-6,708
Prepaid expenses and other assets	-1,450	-711	-1,648
Accounts payable, accrued liabilities and warranty obligations	7,641	16,774	17,275
Deferred revenues	5,587	-18,614	25,443
Net cash used in operating activities	-872	-44,645	-367
Cash flows from investing activities:	'	'	'
Purchases of property and equipment	-6,257	-12,990	-14,662
Net cash used in investing activities	-6,257	-12,990	-14,662
Cash flows from financing activities:	'	'	'
Proceeds from issuance of convertible notes	0	0	20,000
Proceeds from private placement of common stock	0	0	1,858
Principal payments under capital leases	-40	-96	-169
Proceeds from borrowings under term loans	0	10,000	9,898
Repayments of term loans	-2,447	-14,103	-1,863
Proceeds from issuance of common stock under employee stock plans	2,429	255	190
Proceeds from issuance of common stock in IPO, net of underwriting discounts and commissions	0	58,609	0
Net cash (used in) provided by financing activities	-58	51,436	26,482
Effect of exchange rate changes on cash	83	-31	78
Net (decrease) increase in cash and cash equivalents	-7,104	-6,230	11,531
Cash and cash equivalents — Beginning of period	45,294	51,524	39,993
Cash and cash equivalents — End of period	38,190	45,294	51,524
Supplemental disclosures of cash flow information:	'	'	'
Cash paid for interest	1,391	1,681	1,235
Cash paid for income taxes	899	0	0
Non-cash financing and investing activities:	'	'	'
Assets acquired under capital lease	0	0	295
Purchases of property and equipment included in accounts payable	837	772	903
Offering costs not yet paid	0	0	371
Conversion of convertible notes into common stock upon IPO	0	21,204	0
Reclassification of convertible preferred stock warrant liability to additional paid-in capital upon IPO	0	879	0
Common Stock	'	'	'
Cash flows from financing activities:	'	'	'
Payment of offering costs	0	-2,198	-2,585
Convertible debt	'	'	'
Cash flows from financing activities:	'	'	'
Payments of costs related to issuance of convertible notes and financing costs	0	0	-274
Debt, excluding convertible debt	'	'	'
Cash flows from financing activities:	'	'	'
Payments of costs related to issuance of convertible notes and financing costs	$0	($1,031)	($573)

Description_of_Business

Description of Business	12 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
DESCRIPTION OF BUSINESS	'
	DESCRIPTION OF BUSINESS
	Enphase Energy, Inc. and subsidiaries (the “Company”) designs, develops, and sells microinverter systems for the solar photovoltaic industry. The Company was incorporated in 2006 and began selling its products in 2008. The Company’s microinverter system consists of (i) an Enphase microinverter and related accessories that convert direct current (“DC”) power to grid-compliant alternating current (“AC”) power; (ii) an Envoy communications gateway device that collects and transmits performance information from each solar module to the Company’s hosted data center; and (iii) the Enlighten web-based software platform that collects and processes this information to enable customers to monitor and manage their solar power systems. The Company sells microinverter systems primarily to distributors who resell them to solar installers. The Company also sells directly to large installers as well as through original equipment manufacturers (“OEMs”) and strategic partners.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
	Use of Estimates
	The preparation of the Company’s consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ materially from management’s estimates using different assumptions or under different conditions.
	Risks and Uncertainties
	The Company is subject to risks inherent in a business with a limited operating history, including, but not limited to, new and rapidly evolving markets, advances and trends in the development of new technology and services, unfavorable economic and market conditions, competition from larger and more established companies, limited management resources and dependence on a limited number of contract manufacturers and suppliers. The inability to anticipate or to respond adequately to technological developments in the Company's industry, changes in customer or supplier requirements, or changes in regulatory requirements or industry standards could have a material adverse effect on the Company's business and operating results.
	Revenue Recognition
	The Company generates revenue from sales of its microinverter systems, which include microinverter units and related accessories, an Envoy communications gateway device, and an Enlighten web-based monitoring service, to distributors, large installers, OEMs and strategic partners. Enlighten service revenue represented less than 1% of the total revenues for all periods presented.
	Revenues from sales of microinverters and related accessories, and communication gateways are recognized when: (i) persuasive evidence of an arrangement exists; (ii) delivery of the products has occurred in accordance with the terms of the sales agreement and title of and risk of loss have passed to the customer; (iii) the sale price is fixed or determinable; and (iv) collection is reasonably assured. Provisions for rebates, sales incentives, and discounts to customers are accounted for as reductions in revenue in the same period the related sales are recorded.
	Sales of an Envoy communications gateway device include the Enlighten web-based monitoring service. The allocation of revenue between the two deliverables is based on the Company's best estimate of selling price determined by considering multiple factors including, internal costs, gross margin and historical pricing practices. After allocating the overall consideration from such sale to each deliverable using a best estimate of the selling price, (i) revenue from the sale of Envoy devices is recognized upon shipment, assuming all other revenue recognition criteria have been met and (ii) revenue from the web-based monitoring service is recognized ratably over the estimated economic life of the related Envoy devices of 10 years.
	Deferred revenues consist of payments received from customers in advance of revenue recognition for the Company’s products and services described above. As of December 31, 2013 and 2012, deferred revenues consist entirely of service revenue.
	Cost of Revenues
	The Company includes the following in cost of revenues: product costs, warranty, manufacturing personnel and logistics costs, inventory write-downs, hosting services costs related to the Company’s Enlighten service offering, and depreciation and amortization of manufacturing test equipment.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments, such as certificates of deposit and money market instruments with maturities of three months or less at the time of acquisition to be cash equivalents. For all periods presented, its cash balances consist of amounts held in non-interest-bearing deposits and money market accounts.
	Fair Value of Financial Instruments
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to their relatively short-term nature. The carrying values of the Company's variable rate term loans approximate fair value.
	Derivative Instruments
	The Company operates and conducts business in foreign countries where its foreign entities use the local currency as their respective functional currency. As a result, the Company is exposed to movements in foreign currency exchange rates. The Company utilizes foreign currency forward contracts to reduce the impact of foreign currency fluctuations related to anticipated cash receipts from expected future revenues denominated in Euros and intercompany transaction gains or losses. The foreign currency forward contracts are accounted for as derivatives whereby the fair value of the contracts is reported as other current assets or current liabilities in the accompanying consolidated balance sheets, and gains and losses resulting from changes in the fair value are reported in other income (expense), net, in the accompanying consolidated statements of operations.
	Allowances for Doubtful Accounts
	The Company maintains allowances for doubtful accounts for uncollectible accounts receivable. Management estimates anticipated losses from doubtful accounts based on days past due, collection history and the financial health of customers. The allowance for doubtful accounts was $2.0 million and $1.2 million at December 31, 2013 and 2012, respectively. The following table sets forth activities in the allowance for doubtful accounts for the periods indicated:
		December 31,
		2013		2012			2011
	Balance, at beginning of year	$	1,177	$	144		$	17
	Charged to expenses	678		1,068			127
	Charged to Other Accounts	145		(35		)	—
	Balance, at end of year	$	2,000	$	1,177		$	144
	Inventory
	Inventory is valued at the lower of cost or market. The Company determines cost on a first-in first-out basis. Certain factors could affect the realizable value of its inventory, including customer demand and market conditions. Management assesses the valuation on a quarterly basis and writes down the value for any excess and obsolete inventory based upon expected demand, anticipated sales price, effect of new product introductions, product obsolescence, customer concentrations, product merchantability and other factors. Inventory write-downs are equal to the difference between the cost of inventories and their estimated net realizable market value.
	Property and Equipment
	Property and equipment are stated at cost less accumulated depreciation. Cost includes the price paid to acquire or construct the asset as well as any expenditure that substantially adds to the value of or significantly extends the useful life of an existing asset. Repair and maintenance costs are expensed as incurred. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, which range from three to ten years. Leasehold improvements are amortized over the shorter of the lease term or expected useful life of the improvements.
	Capitalized Software Costs
	Internally used software, whether purchased or developed, is capitalized and amortized on a straight-line basis over their estimated useful lives. Costs associated with internally developed software are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they provide additional functionality. Software maintenance and training costs are expensed in the period in which they are incurred. The capitalization of software requires judgment in determining when a project has reached the development stage and the period over which the Company expects to benefit from the use of that software.
	Long-Lived Assets
	Management evaluates long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets.
	Warranty Obligations
	Microinverters Sold Through December 31, 2013
	The Company’s warranty accrual provides for the replacement of microinverter units that fail during the product’s warranty term (15 years for first and second generation microinverters and up to 25 years for third and fourth generation microinverters). On a quarterly basis, the Company employs a consistent, systematic and rational methodology to assess the adequacy of its warranty liability. This assessment includes updating all key estimates and assumptions for each generation of product, based on historical results, trends and the most current data available as of the filing date. The key estimates and assumptions used in the warranty liability are thoroughly reviewed by management on a quarterly basis. The key estimates used by the Company to estimate its warranty liability are: (1) the number of units expected to fail over time (i.e. failure rate); (2) the number of failed units expected to result in warranty claims over time (i.e. claim rate); and (3) the per unit cost of replacement units, including outbound shipping and limited labor costs, expected to be incurred to replace failed units over time (i.e. replacement cost).
	Estimated Failure Rates—The Company’s Quality and Reliability department has primary responsibility to determine the estimated failure rates for each generation of microinverter. To establish initial failure rate estimates for each generation of microinverter, the Company’s quality engineers use a combination of industry standard MTBF (Mean Time Between Failure) estimates for individual components contained in its microinverters, third party data collected on similar equipment deployed in outdoor environments similar to those in which the Company’s microinverters are installed, and rigorous long term reliability and accelerated life cycle testing which simulates the service life of the microinverter in a short period of time. As units are deployed into production environments, the Company continues to monitor product performance via its Enlighten monitoring platform. It typically takes three to nine months between the date of sale and date of end-user installation. Consequently, the Company’s ability to monitor actual failures of units sold similarly lags by three to nine months. When a microinverter fails and is returned, the Company performs diagnostic root cause failure analysis to understand and isolate the underlying mechanism(s) causing the failure. The Company then uses the results of this analysis (combined with the actual, cumulative performance data collected on those units prior to failure via Enlighten) to draw conclusions with respect to how or if the identified failure mechanism(s) will impact the remaining units deployed in the installed base.
	Estimated Claim Rates—Warranty claim rate estimates are based upon assumptions with respect to expected customer behavior over the warranty period. As the vast majority of the Company’s microinverters have been sold to end users for residential applications, the Company believes that warranty claim rates will be affected by changes over time in residential home ownership because the Company expects that subsequent homeowners are less likely to file claims than the homeowners who originally purchase the microinverters.
	Estimated Replacement Costs—Three factors are considered in the Company’s analysis of estimated replacement cost: (1) the estimated cost of replacement microinverters; (2) the estimated cost to ship replacement microinverters to end users; and (3) the estimated labor reimbursement expected to be paid to third party installers performing replacement services for the end user. Because the Company’s warranty provides for the replacement of defective microinverters over long periods of time (either 15 or 25 years, depending on the generation of product purchased), the estimated per unit cost of current and future product generations is considered in the estimated replacement cost. Estimated costs to ship replacement units are based on observable, market-based shipping costs paid by the Company to third party freight carriers. The Company has a separate program that allows third-party installers to claim fixed-dollar reimbursements for labor costs they incur to replace failed microinverter units for a limited time from the date of original installation. Included in the Company’s estimated replacement cost is an analysis of the number of fixed-dollar labor reimbursements expected to be claimed by third party installers over the limited offering period.
	If actual failure rates, claim rates, or replacement costs differ from the Company’s estimates in future periods, changes to these estimates would be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material.
	Fair Value Option for Microinverters Sold Since January 1, 2014
	The Company’s warranty obligations related to microinverters sold since January 1, 2014 provide the Company the right, but not the requirement, to assign its warranty obligations to a third-party. Pursuant to Accounting Standards Codification ("ASC") 820, Fair Value Measurement, such warranties are eligible to be accounted for at fair value. The Company expects to elect the fair value option to measure all eligible microinverter warranties for microinverters sold subsequent to January 1, 2014.
	In addition to the key estimates of failure rates, claim rates and replacement costs described above, the fair value of warranty obligations will require the use of certain Level 3 inputs which are unobservable and significant to the overall fair value measurement. Such additional assumptions will include a discount rate based upon the Company's credit-adjusted risk-free rate and a hypothetical profit margin and risk premium required of a hypothetical market participant to assume the obligation. Warranty obligations initially recorded at fair value (computed using an expected present value technique) at the time of sale will be subsequently re-measured to fair value at each reporting date. In addition, the fair value of the liability will be accreted over the corresponding term of the warranty of up to 25 years using the effective interest method. Any changes in fair value of the liability from period-to-period, including accretion expense, will be recognized in cost of revenues.
	If actual failure rates, claim rates, replacement costs, discount rate or the other additional assumptions differ from the Company’s estimates in future periods, changes to these estimates would be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material.
	As of December 31, 2013, warranty obligations were $30.4 million. Periodic adjustments necessitated by actual experience of claims and any future changes in estimates to this liability associated with sales prior to December 31, 2013 will continue to be accounted for on an undiscounted basis.
	Research and Development Costs
	The Company expenses research and development costs as incurred. Research and development costs totaled $34.5 million, $35.6 million and $25.1 million in 2013, 2012 and 2011, respectively.
	Stock-Based Compensation
	Share-based payments are required to be recognized in the Company’s consolidated statements of operations based on their fair values and the estimated number of shares expected to vest. The Company measures stock-based compensation expense for all share-based payment awards, including stock options made to employees and directors, based on the estimated fair values on the date of the grant. The fair value of stock options granted is estimated using the Black-Scholes option valuation model. The fair value of restricted stock units granted is determined based on the price of the Company's common stock on the date of grant. Stock-based compensation, net of estimated forfeitures, is recognized on a straight-line basis over the requisite service period, which is typically four years.
	Comprehensive Loss
	Comprehensive loss consists of two components, net loss and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that are recorded as an element of stockholders’ equity but are excluded from net income. The Company’s other comprehensive income (loss) consists of foreign currency translation adjustments for all periods presented.
	Income Taxes
	The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized.
	The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. The Company follows accounting for uncertainty in income taxes which requires that the tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.

Inventory

Inventory	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
INVENTORY	'
	INVENTORY
	Inventory as of December 31, 2013 and 2012, consists of the following (in thousands):
		December 31,
		2013		2012
	Raw materials	$	1,428	$	2,223
	Finished goods	15,152		17,620
	Total inventory	$	16,580	$	19,843
	In 2013, no significant write-downs of inventories were made. In 2012 and 2011, the Company recorded write-downs of inventories of $0.8 million and $2.7 million, respectively.

Property_and_Equipment_Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
PROPERTY AND EQUIPMENT, NET	'
	PROPERTY AND EQUIPMENT, NET
	As of December 31, 2013 and 2012, property and equipment, net consists of the following (in thousands):
		Estimated Useful		December 31,
		Life (Years)		2013				2012
	Equipment and machinery	5		$	21,853			$	18,723
	Furniture and fixtures	5–7		2,837				2,788
	Computer equipment	3		1,842				1,688
	Capitalized software	3–5		7,343				5,760
	Leasehold improvements	3–10		5,881				5,642
	Construction in progress			1,703				1,419
	Total			41,459				36,020
	Less accumulated depreciation and amortization			(16,606		)		(10,479		)
	Property and equipment, net			$	24,853			$	25,541
	Depreciation expense was $5.5 million, $4.4 million and $2.3 million for 2013, 2012 and 2011, respectively.
	Capitalized Developed or Purchased Internal-Use Software—Capitalized software costs are being amortized ratably over the estimated useful lives and are included within amortization expense in the amount of $1.5 million, $1.2 million and $0.7 million for 2013, 2012 and 2011, respectively.
	The following table summarizes capitalized internal-use software costs (in thousands):
			December 31, 2013								December 31, 2012
			Gross Cost				Net of				Gross Cost		Net of
							Accumulated						Accumulated
							Amortization						Amortization
	Developed internal-use software		$	3,322			$	1,333			$	2,570	$	1,053
	Purchased software for internal use		4,021				2,311				3,190		2,227
	Total software		$	7,343			$	3,644			$	5,760	$	3,280
	The estimated future aggregate amortization expense for existing internal-use software as of December 31, 2013 is expected to be $1.7 million in 2014, $1.2 million in 2015 and $0.7 million in 2016.

Warranty_Obligations

Warranty Obligations	12 Months Ended
	Dec. 31, 2013
Product Warranties Disclosures [Abstract]	'
WARRANTY OBLIGATIONS	'
	WARRANTY OBLIGATIONS
	The Company’s warranty activities during 2013, 2012 and 2011 were as follows (in thousands):
		December 31,
		2013			2012			2011
	Balance, at beginning of year	$	21,338		8,738			$	2,668
	Accruals for warranties issued during the year	6,303			8,218			5,279
	Changes in estimates	10,303			7,607			1,751
	Settlements	(7,512		)	(3,225		)	(960		)
	Balance, at end of year	30,432			21,338			8,738
	Less current portion included in accrued liabilities	(4,942		)	(6,078		)	(2,005		)
	Long-term portion	$	25,490		$	15,260		$	6,733
	The Company sold approximately 1.0 million second generation microinverters from 2009 through mid-2012. The Company has sold approximately 3.5 million third generation microinverters since mid-2012 and continues to sell such third generation microinverters. The Company has sold 150,000 fourth generation microinverters since mid-2013.
	Changes in Estimates
	On a quarterly basis, the Company uses the best and most complete underlying information available, following a consistent, systematic and rational methodology to determine its warranty obligations. The Company considers all available evidence to assess the reasonableness of all key assumptions underlying its estimated warranty obligations for each generation of microinverter. The changes in estimates discussed below arose from new information available to management and subsequent developments, and accordingly, from better insight and improved judgment. Changes in estimates included in the table above were comprised of the following:
	2013
	In 2013, primarily in the second, third and fourth quarters, the Company experienced actual failures of its second generation microinverters that exceeded its then current failure rate estimate. Based on continuing analysis of field performance data and diagnostic root-cause failure analysis performed on returned units, the Company concluded that it was necessary to increase the estimated failure rates for its second generation product and recorded additional warranty expense of $19.5 million in 2013 (including $3.5 million in the three months ended December 31, 2013). During the third quarter of 2013, the Company recorded a reduction to warranty expense of $3.1 million related to a decrease in the expected failure rate of the Company's third generation product. The Company concluded that there was sufficient historical data of actual field performance of previously sold third generation products to support a lower estimated failure rate.
	In addition, the Company updated its estimated claim rates for its second and third generation products resulting in a decrease to warranty expense of $4.2 million. The revision to estimated claim rates was based on the Company’s observed historical end user behavior and assumptions with respect to expected customer behavior over the 15 or 25 year warranty term.
	Also, the Company decreased warranty expense by $1.9 million (including $1.7 million in the three months ended December 31, 2013), primarily to reflect estimated lower costs to produce fourth generation microinverters to fulfill warranty obligations for second and third generation microinverters.
	2012
	In 2012, primarily in the third and fourth quarters, the Company experienced actual failures of its second generation microinverters that exceeded its then current failure rate estimate. Based on continuing analysis of field performance data and diagnostic root-cause failure analysis performed on returned units, the Company concluded that it was necessary to increase the estimated failure rates for its second generation product and recorded additional warranty expense of $10.2 million in 2012 (including $2.4 million in the three months ended December 31, 2012).
	In the fourth quarter of 2012, the Company revised its claim rate estimate to reflect a decrease in the percentage of end users who are able to access their system’s performance data using the Enlighten monitoring service. Approximately 80 to 90 percent of end users have purchased systems that include Enlighten. End users who have not purchased Enlighten do not have access to the same inverter-level performance data as end users using Enlighten and, consequently are less likely to make warranty claims. In 2012, based on observation of historical results, the Company confirmed that non-Enlighten end users had a lower claim rate than originally estimated. As a result, warranty expense decreased by $0.5 million to reflect this information.
	In addition, the Company recorded a reduction to warranty expense of $2.1 million related to replacement costs, primarily comprised of a $1.9 million reduction in shipping costs. Beginning in the third quarter of 2012, the Company revised its business practice to utilize non-expedited shipping terms for future replacement units, resulting in the reduction in estimated future replacement costs.
	2011
	In 2011, warranty expense included $1.8 million resulting from changes in estimates to reflect increased estimated replacement costs for second generation products.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
FAIR VALUE OF FINANCIAL INSTRUMENTS	'
	FAIR VALUE OF FINANCIAL INSTRUMENTS
	The accounting guidance defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions, and risk of nonperformance.
	The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset’s or liability’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value:
	•	Level 1—Valuations based on quoted prices in active markets for identical assets or liabilities that the Company is able to access. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of such assets or liabilities do not entail a significant degree of judgment.
	•	Level 2—Valuations based on one or more quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly.
	•	Level 3—Valuations based on inputs that are unobservable and significant to the overall fair value measurement.
	Derivative Instruments—The Company utilizes foreign currency forward contracts to reduce the impact of foreign currency fluctuations arising from both sales and purchases denominated in Euros and the British Pound Sterling. As of December 31, 2013 and 2012, the aggregate gross notional amounts of outstanding foreign currency forward contracts were $12.5 million and $6.1 million, respectively. All outstanding open forward contracts at December 31, 2013 matured in January 2014.
	The following table presents the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy at December 31, 2013 and 2012 (in thousands):
		Asset Derivatives				Liability Derivatives
		December 31,		December 31,		December 31,		December 31,
		2013		2012		2013		2012
	Foreign currency forward contracts (Level 2)	$	325	$	—	$	605	$	268
	In 2013 and 2012, the Company recognized net losses of $0.4 million and $0.5 million related to foreign currency forward contracts, respectively.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
LONG-TERM DEBT	'
	LONG-TERM DEBT
	The Company’s long-term debt was comprised of the following at December 31, 2013 and 2012 (in thousands):
		December 31,
		2013			2012
	Term loans	$	7,400		$	7,400
	Equipment financing facility, net of unamortized discount of $31 and $94, respectively	1,277			3,661
	Total debt	8,677			11,061
	Less current portion	(3,507		)	(2,384		)
	Long-term portion	$	5,170		$	8,677
	As of December 31, 2013, the amount of future principal repayments due on the total debt is as follows (in thousands):
	2014	$	3,538
	2015	2,973
	2016	2,197
	Total	$	8,708
	Revolving Credit Facility—The Company has a $50.0 million revolving credit facility (the “Revolver”) with Wells Fargo Bank, N.A. (“Wells Fargo”), which had a maturity date of November 7, 2015. On February 14, 2014, the Company entered into an amendment which granted an automatic extension of the maturity date from November 7, 2015 to November 7, 2016, provided the Company has not borrowed any amounts under the Additional Term Loans made available by Hercules Technology Growth Capital, Inc. ("Hercules") as described below, or otherwise restructure the Additional Term Loans to the satisfaction of Wells Fargo. The amount of loans available to be drawn under the Revolver is subject to a borrowing base calculation that limits availability to a percentage of eligible domestic accounts receivable plus a percentage of the value of eligible domestic inventory, less certain reserves. Wells Fargo and Hercules are parties to an intercreditor agreement, pursuant to which Hercules has a first lien on certain of the Company's assets and a second priority on its other assets. Subject to the intercreditor agreement, loans under the Revolver are secured by a pledge of substantially all of the Company's assets other than intellectual property. Loans under the Revolver bear interest in cash at an annual rate equal to, at the Company's option, either LIBOR or a “base rate” that is comprised of, among other things, the prime rate, plus a margin that is between 1.5% and 4.25% depending on the currency borrowed and the specific term of repayment. The Revolver contains customary affirmative and negative covenants and events of default, and requires the Company to maintain at least $15.0 million of liquidity at all times, of which at least $8.0 million ($5.0 million in the case the maturity date is November 7, 2016) must be undrawn availability. To date, the Company has not drawn on the Revolver and approximately $22.4 million was available for borrowing as of December 31, 2013 based on eligible accounts receivable and inventory balances pursuant to the agreement.
	Term Loans—The Company has a loan and security agreement with Hercules, pursuant to which it borrowed $7.4 million (the "Initial Term Loan"). In addition, the Company may borrow an additional $15.6 million in term loans (the "Additional Term Loans"), which must be drawn, if at all, not later than March 31, 2014. To date, the Company has not, and does not intend to borrow any Additional Term Loans prior to its impending expiration on March 31, 2014. The Company used the proceeds of the Initial Term Loan to replenish cash on hand, which had previously been used to repay the approximately $7.5 million in other outstanding term loans. Loans under the Hercules facility bear interest at an annual rate equal to the higher of (i) the prime rate plus 8.25% or (b) 11.5%. All loans under the Hercules facility will mature on August 1, 2016. Interest is payable in cash on a monthly basis, and the loans will amortize in equal monthly installments commencing on March 1, 2014 for the Initial Term Loan. In addition, the facility includes a $0.6 million end of term charge due on August 1, 2016. Prepayments of loans under the facility are subject to early payment penalties. Loans under the Hercules facility are secured by a pledge of substantially all of the Company's assets other than intellectual property. The Hercules facility does not include any financial covenants. As of December 31, 2013, the outstanding principal balance under the Term Loans was $7.4 million, which solely relates to borrowings under the Initial Term Loan.
	Equipment Financing Facility—The Company has an equipment financing facility with Hercules. The equipment financing facility has a variable interest rate set at the higher of 5.75% above the prime lending rate and 9.0% annually and expires July 1, 2014. This facility is secured by the financed equipment and restricts the Company’s ability to pay dividends and take on certain types of additional liens. As of December 31, 2013, the outstanding principal balance under the equipment financing facility was $1.3 million.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	COMMITMENTS AND CONTINGENCIES
	Operating Leases—The Company leases office facilities under noncancelable operating leases that expire on various dates through 2022. The terms of the lease agreements generally provide for rental payments on a graduated basis, and certain leases require the Company to pay its portion of executory costs such as taxes, insurance, and operating expenses. The Company recognizes rent expense on a straight-line basis over the lease term.
	Rent expense for 2013, 2012 and 2011 was $2.6 million, $2.4 million and $1.2 million, respectively.
	The Company’s minimum lease payments under noncancelable operating leases, exclusive of executory costs, as of December 31, 2013 are as follows (in thousands):
	2014	$	1,672
	2015	1,749
	2016	1,766
	2017	1,555
	2018	1,599
	Thereafter	5,756
	Total minimum lease payments	$	14,097
	Purchase Obligations—The Company has contractual obligations to purchase goods and services, which specify fixed or minimum quantities to be purchased; fixed, minimum, or variable price provisions; and the approximate timing of the transaction. Purchase obligations do not include contracts that may be canceled without penalty.
	The Company utilizes third parties to manufacture its products. As of December 31, 2013, the Company had purchase obligations with third party manufacturers and suppliers totaling approximately $87.6 million. Certain agreements specify future quantities and pricing of products to be supplied by the Company's contract manufacturers for periods up to seven years. Of the $87.6 million included in purchase obligations, $72.5 million are cancelable; however if canceled, the agreement requires the Company to pay cancellation penalties of up to $5.6 million.
	Contingencies —From time to time, the Company may be involved in litigation relating to claims arising out of its operations. The Company is not currently involved in any material legal proceedings. The Company may, however, be involved in material legal proceedings in the future. Such matters are subject to uncertainty and there can be no assurance that such legal proceedings will not have a material adverse effect on its business, results of operations, financial position or cash flows.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
STOCKHOLDERS' EQUITY	'
	STOCKHOLDERS' EQUITY
	Initial Public Offering
	On April 4, 2012, the Company completed its initial public offering ("IPO"), issuing 10,315,151 shares of common stock at an offering price of $6.00 per share. The net proceeds from the sale of the shares were $53.8 million, after deducting the underwriters’ discounts and commissions of $3.3 million and other offering costs of $4.8 million. Upon consummation of the IPO, the Company’s 22,220,856 outstanding shares of convertible preferred stock ($93.6 million carrying value) were automatically converted into 25,171,017 shares of common stock, and the $21.2 million outstanding balance of principal and accrued paid-in-kind interest in convertible notes were automatically converted into 3,533,988 shares of common stock at a conversion price equal to the IPO price of $6.00 per share. As a result, the Company recorded a charge of $2.8 million to interest expense in 2012 for the extinguishment of debt related to the unamortized debt issuance costs and debt discounts.
	Common Stock Warrants
	Prior to its IPO, the Company issued convertible preferred stock warrants in connection with several financing transactions. These warrants automatically converted into warrants to purchase common stock upon the consummation of the IPO.
	As of December 31, 2013, warrants to purchase 293,474 shares of the Company's common stock remained outstanding with exercise prices ranging from $5.27 to $6.17. Such warrants are exercisable and will expire on various dates from 2016 through 2021.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
STOCK-BASED COMPENSATION	'
	STOCK-BASED COMPENSATION
	Description of Equity Incentive Plans
	2006 Plan—Under the Company's 2006 Equity Incentive Plan (the “2006 Plan”), equity awards granted generally vest over a four-year period from the date of grant with a contractual term of up to 10 years. As of December 31, 2013, there were 5.2 million shares of common stock outstanding under the 2006 Plan. No further stock options or other stock awards may be granted under the 2006 Plan.
	2011 Plan—Under the 2011 Equity Incentive Plan (the “2011 Plan”), the Company may, initially, issue up to 2,643,171 shares of its common stock pursuant to stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance-based stock awards, and other forms of equity compensation, or collectively, stock awards, all of which may be granted to employees, including officers, and to non-employee directors and consultants. Options granted under the 2011 Plan before August 1, 2012 generally expire 10 years after the grant date and options granted thereafter generally expire 7 years after the grant date. Equity awards granted under the 2011 Plan generally vest over a four-year period from the date of grant based on continued employment. The number of shares of the Company's common stock authorized for issuance under the 2011 Plan will automatically increase, on each January 1, by 4.5% of the total number of shares of the Company's common stock outstanding on December 31 of the preceding calendar year, or such lesser number of shares of common stock as determined by the board of directors. As of December 31, 2013, 586,524 shares of common stock remained available for issuance pursuant to future grants under the 2011 Plan. On January 1, 2014, the shares authorized for issuance under the 2011 Plan automatically increased by 1,895,541 shares.
	2011 Employee Stock Purchase Plan—The 2011 Employee Stock Purchase Plan (“ESPP”) became effective immediately upon the execution and delivery of the underwriting agreement for the Company’s IPO on March 29, 2012. The ESPP initially authorizes the issuance of 669,603 shares of the Company's common stock pursuant to purchase rights granted to employees. The number of shares of common stock reserved for issuance will automatically increase, on each January 1, by 330,396 shares of the Company's common stock or a lesser number of shares of common stock as determined by the Company's board of directors.
	The ESPP is implemented by concurrent offering periods and each offering period may contain up to four interim purchase periods. In general, offering periods consists of the 24 months periods commencing on each May 1 and November 1 of a calendar year.
	Generally, all full time employees, including executive officers, are eligible to participate in the ESPP. The ESPP permits eligible employees to purchase the Company’s common stock through payroll deductions, which may not exceed 15% of the employee’s total compensation subject to certain limits. Stock may be purchased under the plan at a price equal to 85% of the fair market value of the Company’s stock on either the date of purchase or the first day of an offering period, whichever is lower. A two year look-back feature in the Company's ESPP causes an offering period to reset if the fair value of the Company’s common stock on a purchase date is less than that on the initial offering date for that offering period. The reset feature, when triggered, will be accounted for as a modification to the original offering, resulting in additional expense to be recognized over the 24-month period of the new offering. During any calendar year, participants may not purchase shares of common stock having a value greater than $25,000, based on the fair market value per share of the common stock at the beginning of an offering period.
	As of December 31, 2013, there were 613,984 shares of the Company's common stock available for issuance under the ESPP. On January 1, 2014, the shares authorized for issuance under the ESPP automatically increased by 330,396 shares.
	Valuation of Equity Awards
	Stock Options
	The fair value of each option granted was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions:
	•	Expected term—The expected term of the option awards represents the period of time between the grant date of the option awards and the date the option awards are either exercised, converted or canceled, including an estimate for those option awards still outstanding.
	•	Expected volatility—The Company uses the simplified method, as permitted by the SEC for companies with a limited history of stock option exercise activity, to determine the expected term for its option grants. Expected stock price volatility is determined based on an average of the historical volatilities of the common stock of several companies with characteristics similar to those of the Company.
	•	Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant and with a maturity that approximates the Company's expected term.
	•	Dividend yield—The dividend yield is based on the Company's dividend history and the anticipated dividend payout over its expected term.
	The assumptions used in calculating fair values for stock options granted under the Plan and the resultant weighted-average estimated fair values for the periods presented are as follows:
			Year Ended December 31,
			2013				2012			2011
	Expected term (in years)		4.4				5.7			6
	Expected volatility		68.4		%		74.5		%	72		%
	Annual risk-free rate of return		1		%		0.9		%	1.8		%
	Dividend yield		—		%		—		%	—		%
	Weighted-average fair value on grant date		$	3.84			$	4.69		$	5.08
	Restricted Stock Units
	The fair value of restricted stock units granted is determined based on the price of the Company's common stock on the date of grant.
	Stock-Based Compensation Expense
	The following table summarizes the components of total stock-based compensation expense included in the consolidated statement of operations for the periods presented (in thousands):
			Year Ended December 31,
			2013				2012			2011
	Cost of revenues		$	438			$	196		$	39
	Research and development		2,110				1,728			795
	Sales and marketing		1,812				1,254			671
	General and administrative		2,489				1,588			615
	Total stock-based compensation expense		$	6,849			$	4,766		$	2,120
	The following table summarizes stock-based compensation associated with each type of award:
			Year Ended December 31,
			2013				2012			2011
	Stock options and restricted stock units		$	6,314			$	4,519		$	2,120
	ESPP		535				247			—
	Total stock-based compensation expense		$	6,849			4,766			$	2,120
	As of December 31, 2013, there was approximately $13.2 million of total unrecognized compensation cost related to unvested equity awards, net of expected forfeitures, which is expected to be recognized over a weighted-average period of 2.6 years.
	No income tax benefit has been recognized relating to stock-based compensation expense and no tax benefits have been realized from exercised stock options.
	Equity Awards Activity
	Stock Options
	A summary of the Company’s stock option activity for 2013, 2012 and 2011 is as follows (in thousands, except per share data):
		Shares			Weighted-
					Average
					Exercise Price
					per Share
	Options outstanding — December 31, 2010	5,802			$	0.9
	Granted	1,110			6.16
	Exercised	(502	)		0.38
	Canceled	(154	)		2.82
	Options outstanding — December 31, 2011	6,256			1.83
	Granted	2,478			7.35
	Exercised	(59	)		1.26
	Canceled	(506	)		5.55
	Options outstanding — December 31, 2012	8,169			3.28
	Granted	1,506			7.17
	Exercised	(822	)		1.69
	Canceled	(344	)		7.74
	Options outstanding — December 31, 2013	8,509			3.94
	The following table summarizes information about stock options outstanding at December 31, 2013:
		Options Outstanding								Options Exercisable
Range of Exercise Prices		Number of			Weighted-		Weighted-			Number of		Weighted-
		Shares			Average		Average			Shares		Average
		(in thousands)			Remaining		Exercise			(in thousands)		Exercise
					Life		Price					Price
					(in years)
$0.27 —– $0.91		2,424			5.5		$	0.29		2,424		$	0.29
$1.63 —– $1.63		1,663			6.5		1.63			1,486		1.63
$2.00 —– $5.78		1,209			6.3		3.87			617		3.32
$5.87 —– $7.50		1,379			7.4		6.91			428		7
$7.68 —– $8.82		1,280			7.3		8.09			309		8.26
$9.40 —– $11.00		554			7.7		10.04			287		9.98
Total		8,509			6.6		3.94			5,551		2.45
The intrinsic value of options exercised during 2013 and 2012 was $3.2 million and $0.3 million, respectively. As of December 31, 2013, there were 8.3 million options outstanding that were vested and expected to vest. Such options have a weighted-average exercise price of $3.87 and a weighted-average remaining contractual term of6.5 years. As of December 31, 2013, the aggregate intrinsic value was $23.5 million for the 5.6 million exercisable shares. The intrinsic value is based on the Company’s common stock fair value of $6.34 per share as of December 31, 2013.
Restricted Stock Units
The following is a summary of restricted stock unit activity for 2013 and 2012 (in thousands, except per share data):
	Restricted Stock Units			Weighted Average
				Fair Value per Share at
				Grant Date
Outstanding at December 31, 2011	—			$	—
Granted	282			5.69
Vested	(20	)		2
Canceled	(14	)		6.9
Outstanding at December 31, 2012	248			5.53
Granted	285			6.92
Vested	(107	)		6.08
Canceled	(8	)		7.07
Outstanding at December 31, 2013	418			6.31
The intrinsic value of restricted stock units vested during 2013 and 2012 was $0.8 million and $39,000, respectively. As of December 31, 2013, the restricted stock units outstanding had a weighted average remaining contractual term of 1.6 years with an intrinsic value of $2.6 million.
ESPP
The following is a summary of ESPP activity for 2013 and 2012 and (in thousands, except per share data):
		Year Ended December 31,
		2013				2012
Proceeds from common stock issued under ESPP		$	1,047			$	185
Shares of common stock issued		327				59
Weighted-average price per share		$	3.2			$	3.14

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	No provision for U.S. federal or state income taxes has been made due to cumulative losses since the commencement of operations.
	A provision for income taxes of $0.9 million and $0.7 million has been recognized for 2013 and 2012, respectively, related to the Company's foreign operations.
	A reconciliation of total income tax expense and the amount computed by applying the federal statutory income tax rate of 34% to loss before income taxes for 2013, 2012 and 2011 is as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Income tax benefit at statutory rate	$	(8,517	)	$	(12,773	)	$	(10,883	)
	State taxes, net of federal benefit	(883		)	(1,478		)	(1,956		)
	Change in valuation allowance	8,353			12,574			12,451
	Stock-based compensation	1,191			1,128			479
	Other	455			1,027			(91		)
	Uncertain tax positions	264			173			—
	Provision for income taxes	$	863		$	651		$	—
	A summary of significant components of the Company’s deferred tax assets and liabilities as of December 31, 2013 and 2012 is as follows (in thousands):
		December 31,
		2013			2012
	Current:
	Reserves and allowances	$	14,521		$	11,523
	Valuation allowance	(14,521		)	(11,523		)
	Total current	—			—
	Non-current:
	Net operating losses	16,840			14,364
	Stock-based compensation	1,531			919
	Deferred revenue	2,730			1,425
	Fixed assets and intangibles	11,670			10,301
	Other	476			880
	Valuation allowance	(33,245		)	(27,889		)
	Total non-current	2			—
	Deferred tax liability	—			—
	Net deferred tax assets	$	2		$	—
	Due to the history of losses the Company has generated since inception, the Company believes that it is more-likely-than-not that all of the deferred tax assets will not be realized as of December 31, 2013. Therefore, the Company has recorded a full valuation allowance on its deferred tax assets.
	The Company has net operating loss carryforwards for federal and California income tax purposes of approximately $61.3 million and $53.0 million, respectively, as of December 31, 2013. The federal and state net operating loss carryforwards, if not utilized, will expire beginning in 2026 and 2016, respectively. Utilization of the net operating loss carryforwards may be subject to a substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended (the "Code"), and similar state provisions. The annual limitation may result in the expiration of net operating losses before utilization. The Company has not completed a study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since the Company became a “loss corporation” under the Code. Due to the existence of the valuation allowance, it is not expected that any possible limitation will have an impact on the results of operations or financial position of the Company.
	A share option exercise may result in a tax deduction prior to the actual recognition of the related excess tax benefit because the Company has a net operating loss carryforward. The Company's net operating losses include $201,000 of excess stock option benefits that will be reflected as a credit to additional paid-in capital when utilized.
	The accounting for uncertain tax positions prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company is required to recognize in the financial statements the impact of a tax position, if that position is more-likely-than-not of being sustained on audit, based on the technical merits of the position. The gross unrecognized tax benefits have increased from $160,000 at December 31, 2012 to $376,000 at December 31, 2013, due to increases in tax positions for the current year of $137,000 and increases in tax positions for prior year of $79,000. The unrecognized tax benefits of $376,000 at December 31, 2013, if recognized, would reduce the Company's annual effective tax rate. The Company also accrued interest and penalties of $47,000 related to unrecognized tax benefits during 2013.
	The Company does not have any tax positions for which it is reasonably possible the total amount of gross unrecognized tax benefits will increase or decrease over the next year. The unrecognized tax benefits may increase or change during the next year for items that arise in the ordinary course of business. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense.
	The Company’s tax returns continue to remain subject to examination by U.S. federal authorities for the years 2010 through 2013 and by California state authorities for the years 2009 through 2013.

Concentration_of_Credit_Risk_a

Concentration of Credit Risk and Major Customers	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS	'
	CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS
	The Company is potentially subject to financial instrument concentration of credit risk through its cash and cash equivalents and accounts receivable. The Company places its cash and cash equivalents with high quality institutions and performs periodic evaluations of their relative credit standing. Accounts receivable can be potentially exposed to a concentration of credit risk with its major customers. As of December 31, 2013, the Company had amounts due from two customers that represented 16% and 10% of the total accounts receivable balance. As of December 31, 2012, its two largest accounts receivable balances represented 21% and 16% of the total accounts receivable balance. In 2013, three customers accounted for 15%, 14% and 11% of total net revenues. In 2012, two customers accounted for 16% and 11% of total net revenues. In 2011, three customers accounted for 17%, 11% and 10% of total net revenues.

Net_Loss_Per_Share_Attributabl

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS	'
	NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS
	In April 2012, all of the Company’s then outstanding convertible preferred stock automatically converted into common stock in connection with its IPO. For periods that ended prior to the conversion, basic and diluted net income per common share were presented in conformity with the two-class method required for participating securities.
	Under the two-class method, net loss is allocated between common shares and other participating securities to the extent that the securities are required to share in the losses. The Company’s convertible preferred stock did not meet the definition of a participating security in periods of net losses as the convertible preferred stockholders did not have a contractual obligation to share in the Company’s losses. Accordingly, net losses were attributable to common stockholders. Subsequent to the Company’s IPO and the automatic conversion of the outstanding convertible preferred stock, the Company had no other participating securities and the two-class method is no longer applicable.
	Basic net loss per share attributable to common stockholders is calculated by dividing net loss attributable to common stockholders by the weighted average number of shares outstanding for the period. Diluted net loss per share attributable to common stockholders is calculated by dividing net loss attributable to common stockholders by the weighted average number of common shares and potential dilutive common share equivalents outstanding during the period if the effect is dilutive. The Company’s potentially dilutive common shares include convertible notes and convertible preferred stock prior to their conversion, outstanding stock options and warrants and non-vested restricted stock units.
	The following table presents the potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive (in thousands):
		Year Ended December 31,
		2013	2012	2011
	Convertible preferred stock	—	—	25,171
	Stock options to purchase common stock	8,196	8,174	6,256
	Convertible notes	—	—	2,328
	Unvested restricted stock units	381	248	—
	Warrants to purchase common stock	308	331	143
	Convertible preferred stock warrants	—	—	215
	Total	8,885	8,753	34,113

Segment_and_Geographic_Informa

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
SEGMENT AND GEOGRAPHIC INFORMATION	'
	SEGMENT AND GEOGRAPHIC INFORMATION
	The Company's chief operating decision maker is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis. The Company has one business activity, which entails the design, development, manufacture and sale of microinverter systems for the solar photovoltaic industry. There are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level. Accordingly, management has determined that the Company has a single operating and reportable segment.
	The following tables present net revenues (based on the destination of shipments) and long-lived assets by geographic region as of and for the periods presented (in thousands):
	Net Revenues
		Year Ended December 31,
		2013		2012		2011
	United States	$	192,881	$	189,711	$	128,692
	International	39,965		26,967		20,831
	Total	$	232,846	$	216,678	$	149,523
	Long-Lived Assets
		As of December 31,
		2013		2012		2011
	United States	$	16,262	$	17,136	$	11,199
	China	7,130		6,642		5,974
	Other	1,461		1,763		1,238
	Total	$	24,853	$	25,541	$	18,411

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
RELATED PARTY TRANSACTIONS	'
	RELATED PARTY TRANSACTIONS
	KPCB Holdings, Inc. ("KPCB"), as nominee for certain funds of Kleiner Perkins Caufield & Byers, owned approximately 11 percent of the Company's outstanding stock as of December 31, 2013. Revenues recognized from sales of microinverters to entities that are majority-owned by KPCB entities in 2013, 2012 and 2011 were $2.7 million, $16.8 million and $6.4 million, respectively.

Quarterly_Financial_Informatio

Quarterly Financial Information	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information	'
	Quarterly Financial Information
	(Unaudited)
	(In thousands, except per share data)
		Quarters Ended for Fiscal 2013
		March 31			June 30			September 30			December 31
	Net revenues	$	45,577		$	58,167		$	62,046		$	67,056
	Cost of revenues(1)	33,376			41,883			44,611			45,560
	Gross profit	12,201			16,284			17,435			21,496
	Operating expenses:
	Research and development	9,026			8,484			8,293			8,721
	Sales and marketing	6,850			7,365			8,550			8,315
	General and administrative	6,036			5,926			5,937			6,071
	Total operating expenses	21,912			21,775			22,780			23,107
	Loss from operations	(9,711		)	(5,491		)	(5,345		)	(1,611		)
	Other expense, net	(513		)	(781		)	(815		)	(783		)
	Loss before income taxes	(10,224		)	(6,272		)	(6,160		)	(2,394		)
	Provision for income taxes	(182		)	(124		)	(141		)	(416		)
	Net loss	$	(10,406	)	$	(6,396	)	$	(6,301	)	$	(2,810	)
	Net loss per share, basic and diluted	$	(0.25	)	$	(0.15	)	$	(0.15	)	$	(0.07	)
		Quarters Ended for Fiscal 2012
		March 31			June 30			September 30			December 31
	Net revenues	$	42,600		$	55,697		$	60,813		$	57,568
	Cost of revenues(1)	33,293			42,096			44,489			41,512
	Gross profit	9,307			13,601			16,324			16,056
	Operating expenses:
	Research and development	7,842			8,655			10,571			8,533
	Sales and marketing	5,049			6,360			7,039			7,525
	General and administrative	5,696			6,091			6,911			6,177
	Total operating expenses	18,587			21,106			24,521			22,235
	Loss from operations	(9,280		)	(7,505		)	(8,197		)	(6,179		)
	Other expense, net	(839		)	(3,729		)	(580		)	(1,258		)
	Loss before income taxes	(10,119		)	(11,234		)	(8,777		)	(7,437		)
	Provision for income taxes	(65		)	(151		)	(130		)	(305		)
	Net loss	$	(10,184	)	$	(11,385	)	$	(8,907	)	$	(7,742	)
	Net loss per share, basic and diluted	$	(5.97	)	$	(0.29	)	$	(0.22	)	$	(0.19	)
	-1	See Note 5 to the Consolidated Financial Statements for a description of changes in estimates related to warranty expense in 2013 and 2012.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	'
	Use of Estimates
	The preparation of the Company’s consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ materially from management’s estimates using different assumptions or under different conditions.
Risks and Uncertainties	'
	Risks and Uncertainties
	The Company is subject to risks inherent in a business with a limited operating history, including, but not limited to, new and rapidly evolving markets, advances and trends in the development of new technology and services, unfavorable economic and market conditions, competition from larger and more established companies, limited management resources and dependence on a limited number of contract manufacturers and suppliers. The inability to anticipate or to respond adequately to technological developments in the Company's industry, changes in customer or supplier requirements, or changes in regulatory requirements or industry standards could have a material adverse effect on the Company's business and operating results.
Revenue Recognition	'
	Revenue Recognition
	The Company generates revenue from sales of its microinverter systems, which include microinverter units and related accessories, an Envoy communications gateway device, and an Enlighten web-based monitoring service, to distributors, large installers, OEMs and strategic partners. Enlighten service revenue represented less than 1% of the total revenues for all periods presented.
	Revenues from sales of microinverters and related accessories, and communication gateways are recognized when: (i) persuasive evidence of an arrangement exists; (ii) delivery of the products has occurred in accordance with the terms of the sales agreement and title of and risk of loss have passed to the customer; (iii) the sale price is fixed or determinable; and (iv) collection is reasonably assured. Provisions for rebates, sales incentives, and discounts to customers are accounted for as reductions in revenue in the same period the related sales are recorded.
	Sales of an Envoy communications gateway device include the Enlighten web-based monitoring service. The allocation of revenue between the two deliverables is based on the Company's best estimate of selling price determined by considering multiple factors including, internal costs, gross margin and historical pricing practices. After allocating the overall consideration from such sale to each deliverable using a best estimate of the selling price, (i) revenue from the sale of Envoy devices is recognized upon shipment, assuming all other revenue recognition criteria have been met and (ii) revenue from the web-based monitoring service is recognized ratably over the estimated economic life of the related Envoy devices of 10 years.
	Deferred revenues consist of payments received from customers in advance of revenue recognition for the Company’s products and services described above. As of December 31, 2013 and 2012, deferred revenues consist entirely of service revenue.
Cost of Revenues	'
	Cost of Revenues
	The Company includes the following in cost of revenues: product costs, warranty, manufacturing personnel and logistics costs, inventory write-downs, hosting services costs related to the Company’s Enlighten service offering, and depreciation and amortization of manufacturing test equipment.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company considers all highly liquid investments, such as certificates of deposit and money market instruments with maturities of three months or less at the time of acquisition to be cash equivalents. For all periods presented, its cash balances consist of amounts held in non-interest-bearing deposits and money market accounts.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to their relatively short-term nature. The carrying values of the Company's variable rate term loans approximate fair value.
Derivatives Instruments	'
	Derivative Instruments
	The Company operates and conducts business in foreign countries where its foreign entities use the local currency as their respective functional currency. As a result, the Company is exposed to movements in foreign currency exchange rates. The Company utilizes foreign currency forward contracts to reduce the impact of foreign currency fluctuations related to anticipated cash receipts from expected future revenues denominated in Euros and intercompany transaction gains or losses. The foreign currency forward contracts are accounted for as derivatives whereby the fair value of the contracts is reported as other current assets or current liabilities in the accompanying consolidated balance sheets, and gains and losses resulting from changes in the fair value are reported in other income (expense), net, in the accompanying consolidated statements of operations.
Allowances for Doubtful Accounts	'
	Allowances for Doubtful Accounts
	The Company maintains allowances for doubtful accounts for uncollectible accounts receivable. Management estimates anticipated losses from doubtful accounts based on days past due, collection history and the financial health of customers. The allowance for doubtful accounts was $2.0 million and $1.2 million at December 31, 2013 and 2012, respectively.
Inventory	'
	Inventory
	Inventory is valued at the lower of cost or market. The Company determines cost on a first-in first-out basis. Certain factors could affect the realizable value of its inventory, including customer demand and market conditions. Management assesses the valuation on a quarterly basis and writes down the value for any excess and obsolete inventory based upon expected demand, anticipated sales price, effect of new product introductions, product obsolescence, customer concentrations, product merchantability and other factors. Inventory write-downs are equal to the difference between the cost of inventories and their estimated net realizable market value.
Property and Equipment	'
	Property and Equipment
	Property and equipment are stated at cost less accumulated depreciation. Cost includes the price paid to acquire or construct the asset as well as any expenditure that substantially adds to the value of or significantly extends the useful life of an existing asset. Repair and maintenance costs are expensed as incurred. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, which range from three to ten years. Leasehold improvements are amortized over the shorter of the lease term or expected useful life of the improvements.
Capitalized Software Costs	'
	Capitalized Software Costs
	Internally used software, whether purchased or developed, is capitalized and amortized on a straight-line basis over their estimated useful lives. Costs associated with internally developed software are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they provide additional functionality. Software maintenance and training costs are expensed in the period in which they are incurred. The capitalization of software requires judgment in determining when a project has reached the development stage and the period over which the Company expects to benefit from the use of that software.
Long-Lived Assets	'
	Long-Lived Assets
	Management evaluates long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets.
Warranty Obligations	'
	Warranty Obligations
	Microinverters Sold Through December 31, 2013
	The Company’s warranty accrual provides for the replacement of microinverter units that fail during the product’s warranty term (15 years for first and second generation microinverters and up to 25 years for third and fourth generation microinverters). On a quarterly basis, the Company employs a consistent, systematic and rational methodology to assess the adequacy of its warranty liability. This assessment includes updating all key estimates and assumptions for each generation of product, based on historical results, trends and the most current data available as of the filing date. The key estimates and assumptions used in the warranty liability are thoroughly reviewed by management on a quarterly basis. The key estimates used by the Company to estimate its warranty liability are: (1) the number of units expected to fail over time (i.e. failure rate); (2) the number of failed units expected to result in warranty claims over time (i.e. claim rate); and (3) the per unit cost of replacement units, including outbound shipping and limited labor costs, expected to be incurred to replace failed units over time (i.e. replacement cost).
	Estimated Failure Rates—The Company’s Quality and Reliability department has primary responsibility to determine the estimated failure rates for each generation of microinverter. To establish initial failure rate estimates for each generation of microinverter, the Company’s quality engineers use a combination of industry standard MTBF (Mean Time Between Failure) estimates for individual components contained in its microinverters, third party data collected on similar equipment deployed in outdoor environments similar to those in which the Company’s microinverters are installed, and rigorous long term reliability and accelerated life cycle testing which simulates the service life of the microinverter in a short period of time. As units are deployed into production environments, the Company continues to monitor product performance via its Enlighten monitoring platform. It typically takes three to nine months between the date of sale and date of end-user installation. Consequently, the Company’s ability to monitor actual failures of units sold similarly lags by three to nine months. When a microinverter fails and is returned, the Company performs diagnostic root cause failure analysis to understand and isolate the underlying mechanism(s) causing the failure. The Company then uses the results of this analysis (combined with the actual, cumulative performance data collected on those units prior to failure via Enlighten) to draw conclusions with respect to how or if the identified failure mechanism(s) will impact the remaining units deployed in the installed base.
	Estimated Claim Rates—Warranty claim rate estimates are based upon assumptions with respect to expected customer behavior over the warranty period. As the vast majority of the Company’s microinverters have been sold to end users for residential applications, the Company believes that warranty claim rates will be affected by changes over time in residential home ownership because the Company expects that subsequent homeowners are less likely to file claims than the homeowners who originally purchase the microinverters.
	Estimated Replacement Costs—Three factors are considered in the Company’s analysis of estimated replacement cost: (1) the estimated cost of replacement microinverters; (2) the estimated cost to ship replacement microinverters to end users; and (3) the estimated labor reimbursement expected to be paid to third party installers performing replacement services for the end user. Because the Company’s warranty provides for the replacement of defective microinverters over long periods of time (either 15 or 25 years, depending on the generation of product purchased), the estimated per unit cost of current and future product generations is considered in the estimated replacement cost. Estimated costs to ship replacement units are based on observable, market-based shipping costs paid by the Company to third party freight carriers. The Company has a separate program that allows third-party installers to claim fixed-dollar reimbursements for labor costs they incur to replace failed microinverter units for a limited time from the date of original installation. Included in the Company’s estimated replacement cost is an analysis of the number of fixed-dollar labor reimbursements expected to be claimed by third party installers over the limited offering period.
	If actual failure rates, claim rates, or replacement costs differ from the Company’s estimates in future periods, changes to these estimates would be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material.
	Fair Value Option for Microinverters Sold Since January 1, 2014
	The Company’s warranty obligations related to microinverters sold since January 1, 2014 provide the Company the right, but not the requirement, to assign its warranty obligations to a third-party. Pursuant to Accounting Standards Codification ("ASC") 820, Fair Value Measurement, such warranties are eligible to be accounted for at fair value. The Company expects to elect the fair value option to measure all eligible microinverter warranties for microinverters sold subsequent to January 1, 2014.
	In addition to the key estimates of failure rates, claim rates and replacement costs described above, the fair value of warranty obligations will require the use of certain Level 3 inputs which are unobservable and significant to the overall fair value measurement. Such additional assumptions will include a discount rate based upon the Company's credit-adjusted risk-free rate and a hypothetical profit margin and risk premium required of a hypothetical market participant to assume the obligation. Warranty obligations initially recorded at fair value (computed using an expected present value technique) at the time of sale will be subsequently re-measured to fair value at each reporting date. In addition, the fair value of the liability will be accreted over the corresponding term of the warranty of up to 25 years using the effective interest method. Any changes in fair value of the liability from period-to-period, including accretion expense, will be recognized in cost of revenues.
	If actual failure rates, claim rates, replacement costs, discount rate or the other additional assumptions differ from the Company’s estimates in future periods, changes to these estimates would be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material.
	As of December 31, 2013, warranty obligations were $30.4 million. Periodic adjustments necessitated by actual experience of claims and any future changes in estimates to this liability associated with sales prior to December 31, 2013 will continue to be accounted for on an undiscounted basis.
Research and Development Costs	'
	Research and Development Costs
	The Company expenses research and development costs as incurred. Research and development costs totaled $34.5 million, $35.6 million and $25.1 million in 2013, 2012 and 2011, respectively.
Share-Based Compensation	'
	Stock-Based Compensation
	Share-based payments are required to be recognized in the Company’s consolidated statements of operations based on their fair values and the estimated number of shares expected to vest. The Company measures stock-based compensation expense for all share-based payment awards, including stock options made to employees and directors, based on the estimated fair values on the date of the grant. The fair value of stock options granted is estimated using the Black-Scholes option valuation model. The fair value of restricted stock units granted is determined based on the price of the Company's common stock on the date of grant. Stock-based compensation, net of estimated forfeitures, is recognized on a straight-line basis over the requisite service period, which is typically four years.
Comprehensive Loss	'
	Comprehensive Loss
	Comprehensive loss consists of two components, net loss and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that are recorded as an element of stockholders’ equity but are excluded from net income. The Company’s other comprehensive income (loss) consists of foreign currency translation adjustments for all periods presented.
Income Taxes	'
	Income Taxes
	The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized.
	The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. The Company follows accounting for uncertainty in income taxes which requires that the tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of changes in allowance for doubtful accounts	'
	The following table sets forth activities in the allowance for doubtful accounts for the periods indicated:
		December 31,
		2013		2012			2011
	Balance, at beginning of year	$	1,177	$	144		$	17
	Charged to expenses	678		1,068			127
	Charged to Other Accounts	145		(35		)	—
	Balance, at end of year	$	2,000	$	1,177		$	144

Inventory_Tables

Inventory (Tables)	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
Schedule of inventory	'
	Inventory as of December 31, 2013 and 2012, consists of the following (in thousands):
		December 31,
		2013		2012
	Raw materials	$	1,428	$	2,223
	Finished goods	15,152		17,620
	Total inventory	$	16,580	$	19,843

Property_and_Equipment_Net_Tab

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, plant and equipment	'
	As of December 31, 2013 and 2012, property and equipment, net consists of the following (in thousands):
		Estimated Useful		December 31,
		Life (Years)		2013				2012
	Equipment and machinery	5		$	21,853			$	18,723
	Furniture and fixtures	5–7		2,837				2,788
	Computer equipment	3		1,842				1,688
	Capitalized software	3–5		7,343				5,760
	Leasehold improvements	3–10		5,881				5,642
	Construction in progress			1,703				1,419
	Total			41,459				36,020
	Less accumulated depreciation and amortization			(16,606		)		(10,479		)
	Property and equipment, net			$	24,853			$	25,541
	The following table summarizes capitalized internal-use software costs (in thousands):
			December 31, 2013								December 31, 2012
			Gross Cost				Net of				Gross Cost		Net of
							Accumulated						Accumulated
							Amortization						Amortization
	Developed internal-use software		$	3,322			$	1,333			$	2,570	$	1,053
	Purchased software for internal use		4,021				2,311				3,190		2,227
	Total software		$	7,343			$	3,644			$	5,760	$	3,280

Warranty_Obligations_Tables

Warranty Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Product Warranties Disclosures [Abstract]	'
Changes in the Company's product warranty liability	'
	The Company’s warranty activities during 2013, 2012 and 2011 were as follows (in thousands):
		December 31,
		2013			2012			2011
	Balance, at beginning of year	$	21,338		8,738			$	2,668
	Accruals for warranties issued during the year	6,303			8,218			5,279
	Changes in estimates	10,303			7,607			1,751
	Settlements	(7,512		)	(3,225		)	(960		)
	Balance, at end of year	30,432			21,338			8,738
	Less current portion included in accrued liabilities	(4,942		)	(6,078		)	(2,005		)
	Long-term portion	$	25,490		$	15,260		$	6,733

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Schedule of financial instruments that are measured at fair value on a recurring basis	'
	The following table presents the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy at December 31, 2013 and 2012 (in thousands):
		Asset Derivatives				Liability Derivatives
		December 31,		December 31,		December 31,		December 31,
		2013		2012		2013		2012
	Foreign currency forward contracts (Level 2)	$	325	$	—	$	605	$	268

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Schedule of long-term debt	'
	The Company’s long-term debt was comprised of the following at December 31, 2013 and 2012 (in thousands):
		December 31,
		2013			2012
	Term loans	$	7,400		$	7,400
	Equipment financing facility, net of unamortized discount of $31 and $94, respectively	1,277			3,661
	Total debt	8,677			11,061
	Less current portion	(3,507		)	(2,384		)
	Long-term portion	$	5,170		$	8,677
Schedule of maturities of long-term debt	'
	As of December 31, 2013, the amount of future principal repayments due on the total debt is as follows (in thousands):
	2014	$	3,538
	2015	2,973
	2016	2,197
	Total	$	8,708

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of future minimum rental payments for operating leases	'
	The Company’s minimum lease payments under noncancelable operating leases, exclusive of executory costs, as of December 31, 2013 are as follows (in thousands):
	2014	$	1,672
	2015	1,749
	2016	1,766
	2017	1,555
	2018	1,599
	Thereafter	5,756
	Total minimum lease payments	$	14,097

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of valuation assumptions of stock options	'
	The assumptions used in calculating fair values for stock options granted under the Plan and the resultant weighted-average estimated fair values for the periods presented are as follows:
			Year Ended December 31,
			2013				2012			2011
	Expected term (in years)		4.4				5.7			6
	Expected volatility		68.4		%		74.5		%	72		%
	Annual risk-free rate of return		1		%		0.9		%	1.8		%
	Dividend yield		—		%		—		%	—		%
	Weighted-average fair value on grant date		$	3.84			$	4.69		$	5.08
Schedule of components of stock-based compensation expense in the consolidated statement of operations, by report line	'
	The following table summarizes the components of total stock-based compensation expense included in the consolidated statement of operations for the periods presented (in thousands):
			Year Ended December 31,
			2013				2012			2011
	Cost of revenues		$	438			$	196		$	39
	Research and development		2,110				1,728			795
	Sales and marketing		1,812				1,254			671
	General and administrative		2,489				1,588			615
	Total stock-based compensation expense		$	6,849			$	4,766		$	2,120
Schedule of stock-based compensation expense by award type	'
	The following table summarizes stock-based compensation associated with each type of award:
			Year Ended December 31,
			2013				2012			2011
	Stock options and restricted stock units		$	6,314			$	4,519		$	2,120
	ESPP		535				247			—
	Total stock-based compensation expense		$	6,849			4,766			$	2,120
Schedule of summary of stock option activity	'
	A summary of the Company’s stock option activity for 2013, 2012 and 2011 is as follows (in thousands, except per share data):
		Shares			Weighted-
					Average
					Exercise Price
					per Share
	Options outstanding — December 31, 2010	5,802			$	0.9
	Granted	1,110			6.16
	Exercised	(502	)		0.38
	Canceled	(154	)		2.82
	Options outstanding — December 31, 2011	6,256			1.83
	Granted	2,478			7.35
	Exercised	(59	)		1.26
	Canceled	(506	)		5.55
	Options outstanding — December 31, 2012	8,169			3.28
	Granted	1,506			7.17
	Exercised	(822	)		1.69
	Canceled	(344	)		7.74
	Options outstanding — December 31, 2013	8,509			3.94
Schedule of stock options outstanding under the 2006 and 2011 Plans	'
	The following table summarizes information about stock options outstanding at December 31, 2013:
			Options Outstanding								Options Exercisable
	Range of Exercise Prices		Number of			Weighted-		Weighted-			Number of		Weighted-
			Shares			Average		Average			Shares		Average
			(in thousands)			Remaining		Exercise			(in thousands)		Exercise
						Life		Price					Price
						(in years)
	$0.27 —– $0.91		2,424			5.5		$	0.29		2,424		$	0.29
	$1.63 —– $1.63		1,663			6.5		1.63			1,486		1.63
	$2.00 —– $5.78		1,209			6.3		3.87			617		3.32
	$5.87 —– $7.50		1,379			7.4		6.91			428		7
	$7.68 —– $8.82		1,280			7.3		8.09			309		8.26
	$9.40 —– $11.00		554			7.7		10.04			287		9.98
	Total		8,509			6.6		3.94			5,551		2.45
Schedule of restricted stock unit activity	'
	The following is a summary of restricted stock unit activity for 2013 and 2012 (in thousands, except per share data):
		Restricted Stock Units			Weighted Average
					Fair Value per Share at
					Grant Date
	Outstanding at December 31, 2011	—			$	—
	Granted	282			5.69
	Vested	(20	)		2
	Canceled	(14	)		6.9
	Outstanding at December 31, 2012	248			5.53
	Granted	285			6.92
	Vested	(107	)		6.08
	Canceled	(8	)		7.07
	Outstanding at December 31, 2013	418			6.31
Schedule of summary of ESPP	'
	The following is a summary of ESPP activity for 2013 and 2012 and (in thousands, except per share data):
			Year Ended December 31,
			2013				2012
	Proceeds from common stock issued under ESPP		$	1,047			$	185
	Shares of common stock issued		327				59
	Weighted-average price per share		$	3.2			$	3.14

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Effective Income Tax Rate Reconciliation	'
	A reconciliation of total income tax expense and the amount computed by applying the federal statutory income tax rate of 34% to loss before income taxes for 2013, 2012 and 2011 is as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Income tax benefit at statutory rate	$	(8,517	)	$	(12,773	)	$	(10,883	)
	State taxes, net of federal benefit	(883		)	(1,478		)	(1,956		)
	Change in valuation allowance	8,353			12,574			12,451
	Stock-based compensation	1,191			1,128			479
	Other	455			1,027			(91		)
	Uncertain tax positions	264			173			—
	Provision for income taxes	$	863		$	651		$	—
Schedule of Deferred Tax Assets and Liabilities	'
	A summary of significant components of the Company’s deferred tax assets and liabilities as of December 31, 2013 and 2012 is as follows (in thousands):
		December 31,
		2013			2012
	Current:
	Reserves and allowances	$	14,521		$	11,523
	Valuation allowance	(14,521		)	(11,523		)
	Total current	—			—
	Non-current:
	Net operating losses	16,840			14,364
	Stock-based compensation	1,531			919
	Deferred revenue	2,730			1,425
	Fixed assets and intangibles	11,670			10,301
	Other	476			880
	Valuation allowance	(33,245		)	(27,889		)
	Total non-current	2			—
	Deferred tax liability	—			—
	Net deferred tax assets	$	2		$	—

Net_Loss_Per_Share_Attributabl1

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Schedule of potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'
	The following table presents the potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive (in thousands):
		Year Ended December 31,
		2013	2012	2011
	Convertible preferred stock	—	—	25,171
	Stock options to purchase common stock	8,196	8,174	6,256
	Convertible notes	—	—	2,328
	Unvested restricted stock units	381	248	—
	Warrants to purchase common stock	308	331	143
	Convertible preferred stock warrants	—	—	215
	Total	8,885	8,753	34,113

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Net revenues and long-lived assets by geographic region	'
	Long-Lived Assets
		As of December 31,
		2013		2012		2011
	United States	$	16,262	$	17,136	$	11,199
	China	7,130		6,642		5,974
	Other	1,461		1,763		1,238
	Total	$	24,853	$	25,541	$	18,411
	Net Revenues
		Year Ended December 31,
		2013		2012		2011
	United States	$	192,881	$	189,711	$	128,692
	International	39,965		26,967		20,831
	Total	$	232,846	$	216,678	$	149,523

Quarterly_Financial_Informatio1

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	Quarterly Financial Information
	(Unaudited)
	(In thousands, except per share data)
		Quarters Ended for Fiscal 2013
		March 31			June 30			September 30			December 31
	Net revenues	$	45,577		$	58,167		$	62,046		$	67,056
	Cost of revenues(1)	33,376			41,883			44,611			45,560
	Gross profit	12,201			16,284			17,435			21,496
	Operating expenses:
	Research and development	9,026			8,484			8,293			8,721
	Sales and marketing	6,850			7,365			8,550			8,315
	General and administrative	6,036			5,926			5,937			6,071
	Total operating expenses	21,912			21,775			22,780			23,107
	Loss from operations	(9,711		)	(5,491		)	(5,345		)	(1,611		)
	Other expense, net	(513		)	(781		)	(815		)	(783		)
	Loss before income taxes	(10,224		)	(6,272		)	(6,160		)	(2,394		)
	Provision for income taxes	(182		)	(124		)	(141		)	(416		)
	Net loss	$	(10,406	)	$	(6,396	)	$	(6,301	)	$	(2,810	)
	Net loss per share, basic and diluted	$	(0.25	)	$	(0.15	)	$	(0.15	)	$	(0.07	)
		Quarters Ended for Fiscal 2012
		March 31			June 30			September 30			December 31
	Net revenues	$	42,600		$	55,697		$	60,813		$	57,568
	Cost of revenues(1)	33,293			42,096			44,489			41,512
	Gross profit	9,307			13,601			16,324			16,056
	Operating expenses:
	Research and development	7,842			8,655			10,571			8,533
	Sales and marketing	5,049			6,360			7,039			7,525
	General and administrative	5,696			6,091			6,911			6,177
	Total operating expenses	18,587			21,106			24,521			22,235
	Loss from operations	(9,280		)	(7,505		)	(8,197		)	(6,179		)
	Other expense, net	(839		)	(3,729		)	(580		)	(1,258		)
	Loss before income taxes	(10,119		)	(11,234		)	(8,777		)	(7,437		)
	Provision for income taxes	(65		)	(151		)	(130		)	(305		)
	Net loss	$	(10,184	)	$	(11,385	)	$	(8,907	)	$	(7,742	)
	Net loss per share, basic and diluted	$	(5.97	)	$	(0.29	)	$	(0.22	)	$	(0.19	)
	-1	See Note 5 to the Consolidated Financial Statements for a description of changes in estimates related to warranty expense in 2013 and 2012.

Summary_of_Significant_Account3

Summary of Significant Accounting Policies ( Activities in the Allowance for Doubtful Accounts) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts Receivable [Roll Forward]	'	'	'
Balance, at beginning of year	$1,177	$144	$17
Charged to expenses	678	1,068	127
Charged to Other Accounts	145	-35	0
Balance, at end of year	$2,000	$1,177	$144

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Narrative) (Details) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Allowance for doubtful accounts

$2,000

'

'

'

$1,177

'

'

'

$2,000

$1,177

$144

$17

Warranty obligation

30,432

'

'

'

21,338

'

'

'

30,432

21,338

8,738

2,668

Research and development expense

$8,721

$8,293

$8,484

$9,026

$8,533

$10,571

$8,655

$7,842

$34,524

$35,601

$25,099

'

Stock-based compensation requisite service period

'

'

'

'

'

'

'

'

'4 years

'

'

'

First and Second Generation

'

'

'

'

'

'

'

'

'

'

'

'

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Product warranty, term

'

'

'

'

'

'

'

'

'15 years

'

'

'

Minimum

'

'

'

'

'

'

'

'

'

'

'

'

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Property and equipment estimated useful life

'

'

'

'

'

'

'

'

'3 years

'

'

'

Product warranty, term

'

'

'

'

'

'

'

'

'15 years

'

'

'

Product installation period

'

'

'

'

'

'

'

'

'3 months

'

'

'

Period failure rate measurement lags product sale

'

'

'

'

'

'

'

'

'3 months

'

'

'

Maximum

'

'

'

'

'

'

'

'

'

'

'

'

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Property and equipment estimated useful life

'

'

'

'

'

'

'

'

'10 years

'

'

'

Product warranty, term

'

'

'

'

'

'

'

'

'25 years

'

'

'

Product installation period

'

'

'

'

'

'

'

'

'9 months

'

'

'

Period failure rate measurement lags product sale

'

'

'

'

'

'

'

'

'9 months

'

'

'

Maximum | Third and Fourth Generation

'

'

'

'

'

'

'

'

'

'

'

'

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Product warranty, term

'

'

'

'

'

'

'

'

'25 years

'

'

'

Maximum | Enlighten

'

'

'

'

'

'

'

'

'

'

'

'

Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Percent of revenue represented by product line or service

'

'

'

'

'

'

'

'

1.00%

'

'

'

Revenue recognition period

'

'

'

'

'

'

'

'

'10 years

'

'

'

Inventory_Summary_of_Inventory

Inventory (Summary of Inventory) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of inventory	'	'	'
Raw materials	$1,428,000	$2,223,000	'
Finished goods	15,152,000	17,620,000	'
Total inventory	16,580,000	19,843,000	'
Inventory (Textual) [Abstract]	'	'	'
Inventory write-downs	$0	$800,000	$2,700,000

Property_and_Equipment_Net_Sum

Property and Equipment, Net (Summary of Property and Equipment , Net) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Property and equipment, gross	$41,459,000	$36,020,000	'
Less accumulated depreciation and amortization	-16,606,000	-10,479,000	'
Property and equipment, net	24,853,000	25,541,000	'
Depreciation and amortization	5,500,000	4,400,000	2,300,000
Equipment and machinery	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'5 years	'	'
Property and equipment, gross	21,853,000	18,723,000	'
Furniture and fixtures	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and equipment, gross	2,837,000	2,788,000	'
Computer equipment	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'3 years	'	'
Property and equipment, gross	1,842,000	1,688,000	'
Capitalized software	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and equipment, gross	7,343,000	5,760,000	'
Leasehold improvements	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and equipment, gross	5,881,000	5,642,000	'
Construction in progress	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property and equipment, gross	$1,703,000	$1,419,000	'
Minimum	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'3 years	'	'
Minimum | Furniture and fixtures	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'5 years	'	'
Minimum | Capitalized software	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'3 years	'	'
Minimum | Leasehold improvements	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'3 years	'	'
Maximum	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'10 years	'	'
Maximum | Furniture and fixtures	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'7 years	'	'
Maximum | Capitalized software	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'5 years	'	'
Maximum | Leasehold improvements	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Estimated useful life	'10 years	'	'

Property_and_Equipment_Net_Cap

Property and Equipment, Net (Capitalized Software Costs) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Amortization of capitalized internal use computer software	$1,500,000	$1,200,000	$700,000
Capitalized Computer Software	'	'	'
Gross Cost	7,343,000	5,760,000	'
Net of Accumulated Amortization	3,644,000	3,280,000	'
Internal-use software	'	'	'
Capitalized Computer Software, Future Amortization Expense	'	'	'
2014	1,700,000	'	'
2015	1,200,000	'	'
2016	700,000	'	'
Developed internal-use software	'	'	'
Capitalized Computer Software	'	'	'
Gross Cost	3,322,000	2,570,000	'
Net of Accumulated Amortization	1,333,000	1,053,000	'
Purchased software for internal use	'	'	'
Capitalized Computer Software	'	'	'
Gross Cost	4,021,000	3,190,000	'
Net of Accumulated Amortization	$2,311,000	$2,227,000	'

Warranty_Obligations_Summary_o

Warranty Obligations (Summary of Warranty Obligations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in the Company's product warranty liability	'	'	'
Balance, at beginning of year	$21,338	$8,738	$2,668
Accruals for warranties issued during the year	6,303	8,218	5,279
Changes in estimates	10,303	7,607	1,751
Settlements	-7,512	-3,225	-960
Balance, at end of year	30,432	21,338	8,738
Less current portion included in accrued liabilities	-4,942	-6,078	-2,005
Long-term portion	$25,490	$15,260	$6,733

Warranty_Obligations_Narrative

Warranty Obligations (Narrative) (Details) (USD $)

12 Months Ended

42 Months Ended

3 Months Ended

12 Months Ended

18 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Jun. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Minimum

Maximum

Replacement cost

Claim rate

Shipping cost

Second Generation

Second Generation

Second Generation

Second Generation

Second Generation

Second Generation

Third Generation

Third Generation

Fourth Generation

Fourth Generation

Fourth Generation

Second and Third Generation

Second and Third Generation

Enlighten

Enlighten

unit

Failure rate

Failure rate

Failure rate

Failure rate

Replacement cost

unit

Failure rate

unit

Replacement cost

Replacement cost

Minimum

Maximum

Minimum

Maximum

Product Liability Contingency [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of units sold

'

'

'

'

'

1,000,000

'

'

'

'

'

3,500,000

'

150,000

'

'

'

'

'

'

Increase (decrease) in warranty expense due to changes in warranty variables estimates

'

'

($2.10)

($0.50)

($1.90)

'

$3.50

$2.40

$19.50

$10.20

$1.80

'

($3.10)

'

($1.70)

($1.90)

'

($4.20)

'

'

Product warranty, term

'15 years

'25 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'15 years

'25 years

'

'

Percent of end user customers using performance tracking system

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

80.00%

90.00%

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (Recurring, Level 2, USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Recurring | Level 2	'	'
Asset Derivatives	'	'
Foreign currency forward contracts (Level 2)	$325	$0
Liability Derivatives	'	'
Foreign currency forward contracts (Level 2)	$605	$268

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (Not designated as hedging instrument, Foreign exchange forward, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Not designated as hedging instrument | Foreign exchange forward	'	'
Derivative [Line Items]	'	'
Notional amount of foreign currency	$12.50	$6.10
Net loss on foreign currency	$0.40	$0.50

LongTerm_Debt_Schedule_of_Debt

Long-Term Debt (Schedule of Debt) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of long-term debt	'	'
Total debt	$8,677	$11,061
Less current portion	-3,507	-2,384
Long-term portion	5,170	8,677
Term loans	'	'
Schedule of long-term debt	'	'
Total debt	7,400	7,400
Equipment financing facility, net of unamortized discount of $31 and $94, respectively	'	'
Schedule of long-term debt	'	'
Total debt	1,277	3,661
Net of unamortized discount	$31	$94

LongTerm_Debt_Schedule_of_Matu

Long-Term Debt (Schedule of Maturities) (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]	'
2014	$3,538
2015	2,973
2016	2,197
Total	$8,708

LongTerm_Debt_Narrative_Detail

Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Long-Term Debt (Textual) [Abstract]	'
Long-term debt, gross	8,708,000
Revolving Credit Facility | Wells Fargo Bank	'
Long-Term Debt (Textual) [Abstract]	'
Convertible loan facility, maximum borrowing capacity	50,000,000
Amount of liquidity required for debt compliance	15,000,000
Amount of undrawn credit for debt compliance	8,000,000
Amount of liquidity required for debt compliance	5,000,000
Convertible loan facility, remaining borrowing capacity	22,400,000
Revolving Credit Facility | Wells Fargo Bank | Minimum | LIBOR or Base Rate	'
Long-Term Debt (Textual) [Abstract]	'
Term Loan interest at an prime rate	1.50%
Revolving Credit Facility | Wells Fargo Bank | Maximum | LIBOR or Base Rate	'
Long-Term Debt (Textual) [Abstract]	'
Term Loan interest at an prime rate	4.25%
Term loan | Hercules Technology Growth Capital, Inc	'
Long-Term Debt (Textual) [Abstract]	'
Convertible loan facility, maximum borrowing capacity	7,400,000
Debt instrument additional borrowing amount	15,600,000
Term Loan interest at an annual rate	11.50%
Credit facility, end of term charge	600,000
Long-term debt, gross	7,400,000
Term loan | Hercules Technology Growth Capital, Inc | Prime Rate	'
Long-Term Debt (Textual) [Abstract]	'
Term Loan interest at an prime rate	8.25%
Term loan | Horizon Technology Finance Corporation	'
Long-Term Debt (Textual) [Abstract]	'
Repayment of term loans	7,500,000
Equipment financing facility | Hercules Technology Growth Capital, Inc	'
Long-Term Debt (Textual) [Abstract]	'
Term Loan interest at an annual rate	9.00%
Long-term debt, gross	1,300,000
Equipment financing facility | Hercules Technology Growth Capital, Inc | Prime Rate	'
Long-Term Debt (Textual) [Abstract]	'
Term Loan interest at an prime rate	5.75%

Commitments_and_Contingencies_1

Commitments and Contingencies (Future Minimum Payments for Operating Leases) (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]	'
2014	$1,672
2015	1,749
2016	1,766
2017	1,555
2018	1,599
Thereafter	5,756
Total minimum lease payments	$14,097

Commitments_and_Contingencies_2

Commitments and Contingencies (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies [Line Items]	'	'	'
Rent expense	$2.60	$2.40	$1.20
Purchase obligation	87.6	'	'
Cancelable portion of purchase obligation	72.5	'	'
Purchase obligation cancellation penalties	$5.60	'	'
Maximum	'	'	'
Commitments and Contingencies [Line Items]	'	'	'
Purchase obligation time period	'7 years	'	'

Stockholders_Equity_Narrative_

Stockholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Apr. 04, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]	'	'	'	'
Common stock shares issued during period, in connection with credit facility (shares)	10,315,151	'	'	'
Common stock issued, price per share (usd per share)	$6	'	'	$5.27
Net proceeds from IPO	$53,800,000	$0	$58,609,000	$0
Underwriter's discounts and commissions	3,300,000	'	'	'
Other estimated offering costs	4,800,000	'	'	'
Convertible preferred stock, shares outstanding	22,220,856	0	0	'
Convertible preferred stock outstanding, value	93,600,000	'	'	'
Convertible notes, outstanding balance of principal and accrued paid in kind interest	21,200,000	'	'	'
Conversion of convertible preferred stock into common stock (shares)	25,171,017	'	'	'
Conversion of notes into common stock (shares)	3,533,988	'	'	'
Common stock conversion price per share (usd per share)	$6	'	'	'
Debt interest expense	'	'	$2,800,000	'
Common Stock	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Number of securities called by warrants	'	293,474	'	'
Common Stock | Minimum	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Warrant to purchase common stock, price per share (usd per share)	'	5.27	'	'
Common Stock | Maximum	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Warrant to purchase common stock, price per share (usd per share)	'	6.17	'	'

StockBased_Compensation_Valuat

Stock-Based Compensation (Valuation Assumptions of Stock Options Under Black-Scholes Model) (Details) (Stock options, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock options	'	'	'
The Fair Value of Each Option Granted During the Period [Abstract]	'	'	'
Expected term (in years)	'4 years 4 months 24 days	'5 years 8 months 12 days	'6 years
Expected volatility	68.40%	74.50%	72.00%
Annual risk-free rate of return	1.00%	0.90%	1.80%
Dividend yield	0.00%	0.00%	0.00%
Weighted-average fair value on grant date (usd per share)	$3.84	$4.69	$5.08

StockBased_Compensation_Compon

Stock-Based Compensation (Components of Stock-based Compensation Expense by Report Line) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]	'	'	'
Total stock-based compensation expense	$6,849	$4,766	$2,120
Cost of revenues	'	'	'
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]	'	'	'
Total stock-based compensation expense	438	196	39
Research and development	'	'	'
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]	'	'	'
Total stock-based compensation expense	2,110	1,728	795
Sales and marketing	'	'	'
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]	'	'	'
Total stock-based compensation expense	1,812	1,254	671
General and administrative	'	'	'
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]	'	'	'
Total stock-based compensation expense	$2,489	$1,588	$615

StockBased_Compensation_Expens

Stock-Based Compensation (Expense by Award Type) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense	$6,849	$4,766	$2,120
Stock options and restricted stock units	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense	6,314	4,519	2,120
ESPP	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense	$535	$247	$0

StockBased_Compensation_Stock_

Stock-Based Compensation (Stock Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Shares	'	'	'
Options outstanding, beginning (shares)	8,169	6,256	5,802
Granted (shares)	1,506	2,478	1,110
Exercised (shares)	-822	-59	-502
Canceled (shares)	-344	-506	-154
Options outstanding, ending (shares)	8,509	8,169	6,256
Weighted- Average Exercise Price per Share	'	'	'
Options outstanding, beginning (usd per share)	$3.28	$1.83	$0.90
Granted (usd per share)	$7.17	$7.35	$6.16
Exercised (usd per share)	$1.69	$1.26	$0.38
Canceled (usd per share)	$7.74	$5.55	$2.82
Options outstanding, ending (usd per share)	$3.94	$3.28	$1.83

StockBased_Compensation_Range_

Stock-Based Compensation (Range of Exercise Price) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Number of Shares Outstanding	8,509
Weighted- Average Remaining Life of Outstanding Options (in years)	'6 years 7 months 6 days
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$3.94
Number of Shares Exercisable	5,551
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$2.45
$0.27 – $0.91	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$0.27
Range of Exercise Prices - Upper Range Limit (usd per share)	$0.91
Number of Shares Outstanding	2,424
Weighted- Average Remaining Life of Outstanding Options (in years)	'5 years 6 months
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$0.29
Number of Shares Exercisable	2,424
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$0.29
$1.63 - $1.63	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$1.63
Range of Exercise Prices - Upper Range Limit (usd per share)	$1.63
Number of Shares Outstanding	1,663
Weighted- Average Remaining Life of Outstanding Options (in years)	'6 years 6 months
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$1.63
Number of Shares Exercisable	1,486
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$1.63
$2.00 – $5.78	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$2
Range of Exercise Prices - Upper Range Limit (usd per share)	$5.78
Number of Shares Outstanding	1,209
Weighted- Average Remaining Life of Outstanding Options (in years)	'6 years 3 months 18 days
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$3.87
Number of Shares Exercisable	617
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$3.32
$5.87 - $7.50	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$5.87
Range of Exercise Prices - Upper Range Limit (usd per share)	$7.50
Number of Shares Outstanding	1,379
Weighted- Average Remaining Life of Outstanding Options (in years)	'7 years 4 months 24 days
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$6.91
Number of Shares Exercisable	428
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$7
$7.68 - $8.82	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$7.68
Range of Exercise Prices - Upper Range Limit (usd per share)	$8.82
Number of Shares Outstanding	1,280
Weighted- Average Remaining Life of Outstanding Options (in years)	'7 years 3 months 18 days
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$8.09
Number of Shares Exercisable	309
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$8.26
$9.40 - $11.00	'
Exercise Price Range of Options Outstanding and Options Exercisable [Line Items]	'
Range of Exercise Prices - Lower Range Limit (usd per share)	$9.40
Range of Exercise Prices - Upper Range Limit (usd per share)	$11
Number of Shares Outstanding	554
Weighted- Average Remaining Life of Outstanding Options (in years)	'7 years 8 months 12 days
Weighted- Average Exercise Price of Options Outstanding (usd per share)	$10.04
Number of Shares Exercisable	287
Weighted- Average Exercise Price of Options Exercisable (usd per share)	$9.98

StockBased_Compensation_Restri

Stock-Based Compensation (Restricted Stock Unit Activity) (Details) (Restricted stock units, USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Restricted stock units	'	'
Restricted Stock Units	'	'
Outstanding units, beginning (shares)	248	0
Granted (shares)	285	282
Vested (shares)	-107	-20
Canceled (shares)	-8	-14
Outstanding units, ending (shares)	418	248
Weighted Average Fair Value per Share at Grant Date	'	'
Outstanding units, beginning (usd per share)	$5.53	$0
Granted (usd per share)	$6.92	$5.69
Vested (usd per share)	$6.08	$2
Canceled (usd per share)	$7.07	$6.90
Outstanding units, ending (usd per share)	$6.31	$5.53

StockBased_Compensation_Summar

Stock-Based Compensation (Summary of ESPP activity) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'
Proceeds from common stock issued under ESPP	$1,047	$185
Shares of common stock issued	327	59
Weighted-average price per share (usd per share)	$3.20	$3.14

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)

12 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jan. 02, 2014

Dec. 31, 2013

Dec. 31, 2013

Jan. 02, 2014

Restricted stock units

Restricted stock units

2006 Plan

2006 Plan

2011 Plan

2011 Plan

2011 Plan

2011 Employee Stock Purchase Plan (ESPP)

2011 Employee Stock Purchase Plan (ESPP)

Before August 2012

Subsequent event

After August 2012

purchase_period

Subsequent event

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity awards granted period vest over

'

'

'

'

'

'

'4 years

'

'4 years

'

'

'

'

Equity awards granted contractual term

'

'

'

'

'

'

'

'10 years

'

'

'7 years

'

'

Common stock, shares outstanding (shares)

8,509,000

8,169,000

6,256,000

5,802,000

'

'

5,200,000

'

'

'

'

'

'

Number of shares outstanding, granted (shares)

1,506,000

2,478,000

1,110,000

'

'

'

0

'

'

'

'

'

'

Issue of common stock (in shares)

'

'

'

'

'

'

'

'

2,643,171

'

'

669,603

'

Expiration term of ESPP

'

'

'

'

'

'

'

'

'10 years

'

'

'

'

Increase in number of shares of common stock reserved for issuance under the stock incentive plan

'

'

'

'

'

'

'

'

4.50%

'

'

'

'

Maximum number of shares that be issued pursuant to the exercise of incentive stock options

'

'

'

'

'

'

'

'

586,524

'

'

613,984

'

Increase in shares authorized for issuance under plan

'

'

'

'

'

'

'

'

'

1,895,541

'

'

'

Yearly, share increase in reserved shares

'

'

'

'

'

'

'

'

'

'

'

330,396

330,396

Number of interim purchase periods

'

'

'

'

'

'

'

'

'

'

'

4

'

General duration (in months) of employee stock purchase plan

'

'

'

'

'

'

'

'

'

'

'

'24 months

'

Payroll deductions

'

'

'

'

'

'

'

'

'

'

'

15.00%

'

Fair market value

'

'

'

'

'

'

'

'

'

'

'

85.00%

'

Look-back feature in ESPP

'

'

'

'

'

'

'

'

'

'

'

'2 years

'

Recognition period for additional expense triggered by the reset feature

'

'

'

'

'

'

'

'

'

'

'

'24 months

'

Purchase of common stock

'

'

'

'

'

'

'

'

'

'

'

$25,000

'

Total unrecognized compensation cost

13,200,000

'

'

'

'

'

'

'

'

'

'

'

'

Weighted-average period

'2 years 7 months 6 days

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options exercised

3,200,000

300,000

'

'

'

'

'

'

'

'

'

'

'

Number of options outstanding that were vested and expected to vest

8,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Weighted-average fair value, vested (in usd per share)

$3.87

'

'

'

'

'

'

'

'

'

'

'

'

Weighted-average remaining contractual term, vested

'6 years 6 months

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate intrinsic value, exercisable shares

23,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares exercisable

5,551,000

'

'

'

'

'

'

'

'

'

'

'

'

Common stock fair value (in usd per share)

$6.34

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of units vested

'

'

'

'

800,000

39,000

'

'

'

'

'

'

'

Weighted average remaining contractual term

'

'

'

'

'1 year 7 months 6 days

'

'

'

'

'

'

'

'

Intrinsic value of restricted stock units outstanding

'

'

'

'

$2,600,000

'

'

'

'

'

'

'

'

Income_Taxes_Effective_Income_

Income Taxes (Effective Income Tax Reconciliation) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effective Income Tax Rate Reconciliation, Percent [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Income tax benefit at statutory rate	'	'	'	'	'	'	'	'	($8,517)	($12,773)	($10,883)
State taxes, net of federal benefit	'	'	'	'	'	'	'	'	-883	-1,478	-1,956
Change in valuation allowance	'	'	'	'	'	'	'	'	8,353	12,574	12,451
Stock-based compensation	'	'	'	'	'	'	'	'	1,191	1,128	479
Other	'	'	'	'	'	'	'	'	455	1,027	-91
Uncertain tax positions	'	'	'	'	'	'	'	'	264	173	0
Provision for income taxes	$416	$141	$124	$182	$305	$130	$151	$65	$863	$651	$0

Income_Taxes_Deferred_Tax_Asse

Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current:	'	'
Reserves and allowances	$14,521	$11,523
Valuation allowance	-14,521	-11,523
Total current	0	0
Non-current:	'	'
Net operating losses	16,840	14,364
Stock-based compensation	1,531	919
Deferred revenue	2,730	1,425
Fixed assets and intangibles	11,670	10,301
Other	476	880
Valuation allowance	-33,245	-27,889
Total non-current	2	0
Deferred tax liability	0	0
Net deferred tax assets	$2	$0

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]	'	'	'
Provision for income taxes related to foreign operations	$900,000	$700,000	'
Federal statutory income tax rate	34.00%	34.00%	34.00%
Net operating losses from excess stock option benefits	201,000	'	'
Unrecognized tax benefits	376,000	160,000	'
Unrecognized tax benefits, increases in tax positions for the current year	137,000	'	'
Unrecognized tax benefits, increases in tax positions for prior year	79,000	'	'
Unrecognized tax benefits, accrued interest and penalties	47,000	'	'
Internal Revenue Service (IRS)	'	'	'
Income Taxes [Line Items]	'	'	'
Operating loss carryforwards	61,300,000	'	'
California	'	'	'
Income Taxes [Line Items]	'	'	'
Operating loss carryforwards	$53,000,000	'	'

Concentration_of_Credit_Risk_a1

Concentration of Credit Risk and Major Customers (Narrative) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	customer	customer	customer
Accounts Receivable | Credit Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Number of customers considered to give rise to concentration risk	2	2	'
Net Revenue | Customer Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Number of customers considered to give rise to concentration risk	3	2	3
Customer Providing Largest Concentration of Receivable | Accounts Receivable | Credit Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of concentration risk	16.00%	21.00%	'
Customer Providing Second Largest Concentration of Receivable | Accounts Receivable | Credit Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of concentration risk	10.00%	16.00%	'
Customer Accounting for the Largest Concentration of Revenue | Net Revenue | Customer Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of concentration risk	15.00%	16.00%	17.00%
Customer Accounting for Second Largest Concentration of Revenue | Net Revenue | Customer Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of concentration risk	14.00%	11.00%	11.00%
Customer Accounting for Third Largest Concentraion | Net Revenue | Customer Concentration Risk	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of concentration risk	11.00%	'	10.00%

Net_Loss_Per_Share_Attributabl2

Net Loss Per Share Attributable to Common Stockholders (Potential Common Shares Outstanding Excluded from Computation of Diluted Net Loss Per Share) (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	8,885	8,753	34,113
Convertible preferred stock	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	0	0	25,171
Stock options to purchase common stock	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	8,196	8,174	6,256
Convertible notes	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	0	0	2,328
Unvested restricted stock units	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	381	248	0
Warrants to purchase common stock	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	308	331	143
Convertible preferred stock warrants	'	'	'
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders	'	'	'
Total	0	0	215

Segment_and_Geographic_Informa2

Segment and Geographic Information (Net Revenues) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	$67,056	$62,046	$58,167	$45,577	$57,568	$60,813	$55,697	$42,600	$232,846	$216,678	$149,523
United States	'	'	'	'	'	'	'	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	192,881	189,711	128,692
International	'	'	'	'	'	'	'	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	$39,965	$26,967	$20,831

Segment_and_Geographic_Informa3

Segment and Geographic Information (Long-Lived Assets) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Long-lived assets by geographic region	'	'	'
Total	$24,853	$25,541	$18,411
United States	'	'	'
Long-lived assets by geographic region	'	'	'
Total	16,262	17,136	11,199
China	'	'	'
Long-lived assets by geographic region	'	'	'
Total	7,130	6,642	5,974
Other	'	'	'
Long-lived assets by geographic region	'	'	'
Total	$1,461	$1,763	$1,238

Related_Party_Transactions_Nar

Related Party Transactions (Narrative) (Details) (KPCB Holdings, Inc., USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
KPCB Holdings, Inc.	'	'	'
Related Party Transaction [Line Items]	'	'	'
Percentage of Company owned by related party	11.00%	'	'
Revenue from related parties	$2.70	$16.80	$6.40

Quarterly_Financial_Informatio2

Quarterly Financial Information (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	$67,056	$62,046	$58,167	$45,577	$57,568	$60,813	$55,697	$42,600	$232,846	$216,678	$149,523
Cost of revenues	45,560	44,611	41,883	33,376	41,512	44,489	42,096	33,293	165,430	161,390	120,454
Gross profit	21,496	17,435	16,284	12,201	16,056	16,324	13,601	9,307	67,416	55,288	29,069
Operating expenses:	'	'	'	'	'	'	'	'	'	'	'
Research and development	8,721	8,293	8,484	9,026	8,533	10,571	8,655	7,842	34,524	35,601	25,099
Sales and marketing	8,315	8,550	7,365	6,850	7,525	7,039	6,360	5,049	31,080	25,973	17,454
General and administrative	6,071	5,937	5,926	6,036	6,177	6,911	6,091	5,696	23,970	24,875	15,228
Total operating expenses	23,107	22,780	21,775	21,912	22,235	24,521	21,106	18,587	89,574	86,449	57,781
Loss from operations	-1,611	-5,345	-5,491	-9,711	-6,179	-8,197	-7,505	-9,280	-22,158	-31,161	-28,712
Other expense, net	-783	-815	-781	-513	-1,258	-580	-3,729	-839	-2,892	-6,406	-3,578
Loss before income taxes	-2,394	-6,160	-6,272	-10,224	-7,437	-8,777	-11,234	-10,119	-25,050	-37,567	-32,290
Provision for income taxes	-416	-141	-124	-182	-305	-130	-151	-65	-863	-651	0
Net loss attributable to common stockholders	($2,810)	($6,301)	($6,396)	($10,406)	($7,742)	($8,907)	($11,385)	($10,184)	($25,913)	($38,218)	($32,290)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	($0.07)	($0.15)	($0.15)	($0.25)	($0.19)	($0.22)	($0.29)	($5.97)	($0.62)	($1.24)	($25.73)