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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2013	Oct. 31, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	Enphase Energy, Inc.
Entity Central Index Key	0001463101
Document Type	10-Q
Document Period End Date	Sep. 30, 2013
Amendment Flag	false
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		42,041,741

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 31,778	$ 45,294
Accounts receivable, net of allowances of $1,460 and $1,177	34,744	27,743
Inventory	24,392	19,843
Prepaid expenses and other	3,153	2,118
Total current assets	94,067	94,998
Property and equipment, net	24,823	25,541
Other assets	1,420	1,752
Total assets	120,310	122,291
Current liabilities:
Accounts payable	15,103	11,272
Accrued liabilities	20,909	19,266
Deferred revenues	2,980	933
Current portion of term loans	3,432	2,384
Total current liabilities	42,424	33,855
Long-term liabilities:
Deferred revenues	10,325	7,537
Warranty obligations	20,932	15,260
Other liabilities	435	307
Term loans	5,861	8,677
Total liabilities	79,977	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; 41,813 and 40,856 shares issued and outstanding as of September 30, 2013 and December 31, 2012, respectively	0	0
Additional paid-in capital	190,265	183,629
Accumulated deficit	(150,129)	(127,026)
Accumulated other comprehensive income	197	52
Total stockholders’ equity	40,333	56,655
Total liabilities and stockholders’ equity	$ 120,310	$ 122,291

Condensed Consolidated Balance Sheets (Unaudited ) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Allowances, accounts receivable	$ 1,460	$ 1,177
Common stock, par value (usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	41,813,000	40,856,000
Common stock, shares outstanding	41,813,000	40,856,000
Preferred stock, par value (usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net revenues	$ 62,046	$ 60,813	$ 165,790	$ 159,110
Cost of revenues	44,611	44,489	119,870	119,878
Gross profit	17,435	16,324	45,920	39,232
Operating expenses:
Research and development	8,293	10,571	25,803	27,068
Sales and marketing	8,550	7,039	22,765	18,448
General and administrative	5,937	6,911	17,899	18,698
Total operating expenses	22,780	24,521	66,467	64,214
Loss from operations	(5,345)	(8,197)	(20,547)	(24,982)
Other income (expense), net:
Interest expense	(437)	(527)	(1,385)	(5,411)
Other income (expense)	(378)	(53)	(724)	263
Total other expense, net	(815)	(580)	(2,109)	(5,148)
Loss before income taxes	(6,160)	(8,777)	(22,656)	(30,130)
Provision for income taxes	(141)	(130)	(447)	(346)
Net loss attributable to common stockholders	$ (6,301)	$ (8,907)	$ (23,103)	$ (30,476)
Net loss per share attributable to common stockholders, basic and diluted (usd per share)	$ (0.15)	$ (0.22)	$ (0.56)	$ (1.11)
Shares used in computing net loss per share attributable to common stockholders, basic and diluted	41,777	40,755	41,517	27,356

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net loss attributable to common stockholders	$ (6,301)	$ (8,907)	$ (23,103)	$ (30,476)
Other comprehensive (loss) income:
Foreign currency translation adjustments	104	(102)	145	(85)
Comprehensive loss attributable to common stockholders	$ (6,197)	$ (9,009)	$ (22,958)	$ (30,561)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
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-Name Regulation S-X (SX)
-Number 210
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-Paragraph 19
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Reference 10: http://www.xbrl.org/2003/role/presentationRef
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-Name Regulation S-X (SX)
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+ Details

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (23,103)	$ (30,476)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,122	3,938
Provision for doubtful accounts	665	60
Net loss on disposal of assets	82	110
Non-cash interest expense	322	3,969
Stock-based compensation	4,955	3,159
Change in fair value of convertible preferred stock warrants	0	(520)
Changes in operating assets and liabilities:
Accounts receivable	(7,666)	(15,023)
Inventory	(4,549)	(5,422)
Prepayment to supplier	0	(5,000)
Prepaid expenses and other assets	(969)	(448)
Accounts payable, accrued and other liabilities	11,855	13,543
Deferred revenues	4,835	(20,164)
Net cash used in operating activities	(8,451)	(52,274)
Cash flows from investing activities:
Purchases of property and equipment	(4,886)	(11,054)
Net cash used in investing activities	(4,886)	(11,054)
Cash flows from financing activities:
Proceeds from term loans and debt	0	2,600
Repayments of term loans	(1,815)	(5,522)
Principal payments under capital leases	(40)	(96)
Proceeds from issuance of common stock under employee stock plans	1,672	47
Proceeds from issuance of common stock in IPO, net of underwriting discounts and commissions	0	58,609
Payment of offering costs	0	(2,032)
Net cash (used in) provided by financing activities	(183)	53,606
Effect of exchange rate changes on cash	4	(85)
Net (decrease) increase in cash and cash equivalents	(13,516)	(9,807)
Cash and cash equivalents—Beginning of period	45,294	51,524
Cash and cash equivalents—End of period	31,778	41,717
Supplemental disclosures of cash flow information:
Cash paid for interest	1,069	1,250
Noncash financing and investing activities:
Purchases of property and equipment included in accounts payable	302	412
Conversion of convertible notes into common stock upon IPO	0	21,204
Reclassification of convertible preferred stock warrant liability to additional paid-in capital upon IPO	$ 0	$ 879

Overview and Summary of Significant Accounting Policies	9 Months Ended
Overview and Summary of Significant Accounting Policies	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Overview and Summary of Significant Accounting Policies	Overview and Summary of Significant Accounting Policies The Company Enphase Energy, Inc. ("Enphase" or the “Company”) designs, develops, and sells microinverter systems for the solar photovoltaic industry. 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. 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 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 Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States. The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in the consolidation. Unaudited Interim Financial Information These accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for interim financial reporting. In the opinion of management, these unaudited condensed consolidated interim financial statements reflect all adjustments, consisting of normal recurring items, considered necessary to present fairly the Company's financial condition, results of operations, comprehensive loss and cash flows for the periods indicated. The results of operations for the three and nine months ended September 30, 2013 are not necessarily indicative of the operating results for the full year. Certain information and footnote disclosures typically included in annual consolidated financial statements have been condensed or omitted. Accordingly, these unaudited interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2012. Significant Accounting Policies There have been no material changes in the Company's significant accounting policies, as compared to the significant accounting policies described in the Company's Annual Report on Form 10-K for the year ended December 31, 2012. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions about future events, and apply judgments that affect the reported amounts of assets, liabilities, revenue, expenses and the related disclosures. Significant estimates and assumptions reflected in the financial statements include revenue recognition, inventory valuation and accrued warranty obligations. Actual results could differ from those estimates.

Inventory

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

INVENTORY

Inventory as of September 30, 2013 and December 31, 2012 consists of the following (in thousands):



	September 30, 2013		December 31, 2012
Raw materials	$	1,553	$	2,223
Finished goods	22,839		17,620
Total inventory	$	24,392	$	19,843

Warranty Obligations

9 Months Ended

Sep. 30, 2013

Product Warranties Disclosures [Abstract]

WARRANTY OBLIGATIONS

The Company’s warranty activities during the three and nine months ended September 30, 2013 and 2012 were as follows (in thousands):



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Balance, at beginning of period	$	26,777		$	11,412		$	21,338		$	8,738
Accruals for warranties issued during the period	1,392			2,515			4,802			6,571
Changes in estimates	3,823			2,896			8,537			2,539
Settlements	(2,626		)	(1,330		)	(5,311		)	(2,355		)
Balance, at end of period	$	29,366		$	15,493		$	29,366		$	15,493
Current portion included in accrued liabilities							$	8,434		$	3,589
Long-term portion							$	20,932		$	11,904

Included within warranty expense in the three and nine months ended September 30, 2013 were net changes in estimates of $3.8 million and $8.5 million, respectively. During the three and nine months ended September 30, 2013, 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 $7.3 million and $15.9 million for the three and nine months ended September 30, 2013, respectively. In addition, the Company recorded a reduction to warranty expense of $3.1 million for the three and nine months ended September 30, 2013 related to a decrease in the expected failure rate of the Company's third generation product. During the third quarter of 2013, 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. Further decreases to warranty expense were $0.4 million and $0.1 million of net decreases in estimated replacement costs for the three and nine months ended September 30, 2013, respectively. In addition, for the nine months ended September 30, 2013, the Company updated its estimated claim rates for all product generations 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 warranty term (15 years for first and second generation products, up to 25 years for third and fourth generation products).

Included within warranty expense in the three and nine months ended September 30, 2012 were net changes in estimates of $2.9 million and $2.5 million, respectively. During the three and nine months ended September 30, 2012, 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 $4.8 million and $4.4 million for the three and nine months ended September 30, 2012, respectively. In addition, the Company recorded a reduction to warranty expense of $1.9 million for the three and nine months ended September 30, 2012. During the third quarter of 2012, the Company updated the estimated per unit shipping cost for replacement units delivered to customers and reduced warranty expense to reflect a revision in its business practice. Prior to the third quarter of 2012, the Company’s business practice was to expedite shipment of all replacement units to customers to fulfill warranty claims. These shipping costs are included in the Company’s estimate of total per unit replacement cost. 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.

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 to the Company’s warranty obligations. Such increases or decreases could be material.

Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

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 September 30, 2013 and December 31, 2012, the aggregate gross notional amounts of outstanding foreign currency forward contracts, all with maturities of less than one year, were $20.7 million and $6.1 million, respectively.

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 September 30, 2013 and December 31, 2012 (in thousands):



	Asset Derivatives				Liability Derivatives
	September 30, 2013		December 31, 2012		September 30, 2013		December 31, 2012
Foreign currency forward contracts (Level 2)	$	94	$	—	$	863	$	268

For the three and nine months ended September 30, 2013, the Company recognized net losses of $0.6 million related to foreign currency forward contracts.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Long-Term Debt

9 Months Ended

Sep. 30, 2013

Long-term Debt, by Current and Noncurrent [Abstract]

LONG-TERM DEBT

The Company’s long-term debt at September 30, 2013 and December 31, 2012 consists of the following (in thousands):



	September 30, 2013			December 31, 2012
Term loans	$	7,400		$	7,400
Equipment financing facility, net of unamortized discount of $47 and $94, respectively	1,893			3,661
Total debt	9,293			11,061
Less current portion	(3,432		)	(2,384		)
Long-term portion	$	5,861		$	8,677

As of September 30, 2013, the Company was a party to three debt agreements: (i) the $50.0 million revolving credit facility (the "Revolver") with Wells Fargo Bank, N.A., (ii) the facility with Hercules Technology Growth Capital, Inc. (“Hercules Facility”) consisting of a $7.4 million initial term loan and lending commitments of up to $15.6 million in additional term loans, and (iii) the $5.0 million equipment financing facility, also with Hercules. As of September 30, 2013, the Company has not drawn upon the Revolver or additional term loans available under the Hercules Facility. Each of these debt agreements is described in greater detail in the consolidated financial statements and related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2012.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Contingencies —The Company is not currently involved in any material legal proceedings. The Company may become involved in various legal proceedings and claims that arise in the ordinary course of business. 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.

Stock-Based Compensation

9 Months Ended

Sep. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

STOCK-BASED COMPENSATION

The Company has adopted certain equity incentive and stock purchase plans as described in the consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

Stock Options

The following is a summary of stock option activity for the nine months ended September 30, 2013 (in thousands, except per share data):



	Number of Shares Outstanding		Weighted- Average Exercise Price per Share
Outstanding at December 31, 2012	8,169		$	3.28
Granted	1,417		7.15
Exercised	(773	)	1.65
Canceled	(300	)	7.73
Outstanding at September 30, 2013	8,513		3.92

The total fair value of options exercised in the nine months ended September 30, 2013 was $2.9 million. As of September 30, 2013, the intrinsic value of options outstanding was $31.7 million based on the closing price of the Company's stock as of September 30, 2013.

Restricted Stock Units

The following is a summary of restricted stock unit activity for the nine months ended September 30, 2013 (in thousands, except per share data):



	Restricted Stock Units		Weighted Average Fair Value per Share at Grant Date
Outstanding at December 31, 2012	248		$	5.53
Granted	285		6.92
Vested	(37	)	6.64
Canceled	(5	)	6.90
Outstanding at September 30, 2013	491		6.24

The total fair value of restricted stock units that vested in the nine months ended September 30, 2013 was $0.3 million. As of September 30, 2013, the intrinsic value of restricted stock units outstanding was $4.0 million based on the closing price of the Company's stock as of September 30, 2013.

Stock-Based Compensation Expense

Compensation cost for all stock-based awards expected to vest is measured at fair value on the date of grant and recognized ratably over the requisite service period. The following table summarizes the components of total stock-based compensation expense included in the condensed consolidated statements of operations for the periods presented (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenues	$	137	$	62	$	309	$	119
Research and development	625		514		1,541		1,171
Sales and marketing	542		362		1,317		826
General and administrative	741		513		1,788		1,043
Total	$	2,045	$	1,451	$	4,955	$	3,159

The following table summarizes stock-based compensation associated with each type of award for the periods presented (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Stock options and restricted stock units	$	1,871	$	1,451	$	4,588	$	3,159
Employee Stock Purchase Plan	174		—		367		—
Total	$	2,045	$	1,451	$	4,955	$	3,159

Valuation Assumptions

The fair value of option awards is estimated on the date of the grant using the Black-Scholes option pricing model with the following input 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 our expected term.


•	Dividend yield—The dividend yield is based on our dividend history and the anticipated dividend payout over our expected term.

The following table presents the weighted-average assumptions used to estimate the fair values of the stock options granted in the periods presented:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Expected term (in years)	4.4			4.8			4.4			5.8
Expected volatility	67.2		%	78.0		%	68.7		%	74.4		%
Annual risk-free rate of return	1.2		%	0.6		%	1.0		%	0.9		%
Dividend yield	0.0		%	0.0		%	0.0		%	0.0		%
Weighted average grant date fair value	$	4.07		$	3.15		$	3.84		$	4.82

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.

As of September 30, 2013, there was approximately $14.6 million of total unrecognized compensation cost related to unvested equity awards expected to be recognized over a weighted-average period of 2.7 years.

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 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. The Company had a provision for income taxes of $141,000 and $130,000 for the three months ended September 30, 2013 and 2012, respectively, and $447,000 and $346,000 for the nine months ended September 30, 2013 and 2012, respectively. The provision relates to the Company's subsidiaries located outside of the United States.

Net Loss Per Share Attributable to Common Stockholders

9 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

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 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. The disproportional change in loss per share for the nine months ended September 30, 2013, as compared to the same period in the prior year, is attributed to the effect of the IPO of 10.3 million shares of its common stock. In addition, the IPO also effected the automatic conversion of the Company's convertible preferred stock and convertible notes into 28.7 million shares of its common stock.

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, shares issuable pursuant to the ESPP 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 three and nine months ended September 30, 2013 and 2012, respectively, because including them would have been anti-dilutive (in thousands):



	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012
Stock options to purchase common stock	8,493	8,180	8,095	8,420
Restricted stock units	482	132	363	268
Warrants to purchase common stock	293	331	312	331
Total	9,268	8,643	8,770	9,019

Related Party Transactions	9 Months Ended
Related Party Transactions	Sep. 30, 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 12 percent of the Company's outstanding stock as of September 30, 2013. Revenues recognized from sales of microinverters to entities that are majority-owned by KPCB entities were $0.6 million and $0 in the three months ended September 30, 2013 and 2012, respectively, and $2.7 million and $16.8 million in the nine months ended September 30, 2013 and 2012, respectively.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Overview and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation, Consolidation and Related Party Transactions	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States. The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in the consolidation.
Unaudited Interim Financial Information	Unaudited Interim Financial Information These accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for interim financial reporting. In the opinion of management, these unaudited condensed consolidated interim financial statements reflect all adjustments, consisting of normal recurring items, considered necessary to present fairly the Company's financial condition, results of operations, comprehensive loss and cash flows for the periods indicated. The results of operations for the three and nine months ended September 30, 2013 are not necessarily indicative of the operating results for the full year. Certain information and footnote disclosures typically included in annual consolidated financial statements have been condensed or omitted. Accordingly, these unaudited interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2012.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes in the Company's significant accounting policies, as compared to the significant accounting policies described in the Company's Annual Report on Form 10-K for the year ended December 31, 2012.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions about future events, and apply judgments that affect the reported amounts of assets, liabilities, revenue, expenses and the related disclosures. Significant estimates and assumptions reflected in the financial statements include revenue recognition, inventory valuation and accrued warranty obligations. Actual results could differ from those estimates.

Inventory (Tables)

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Schedule of inventory

Inventory as of September 30, 2013 and December 31, 2012 consists of the following (in thousands):



	September 30, 2013		December 31, 2012
Raw materials	$	1,553	$	2,223
Finished goods	22,839		17,620
Total inventory	$	24,392	$	19,843

Warranty Obligations (Tables)

9 Months Ended

Sep. 30, 2013

Product Warranties Disclosures [Abstract]

Changes in the Company's product warranty liability

The Company’s warranty activities during the three and nine months ended September 30, 2013 and 2012 were as follows (in thousands):



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Balance, at beginning of period	$	26,777		$	11,412		$	21,338		$	8,738
Accruals for warranties issued during the period	1,392			2,515			4,802			6,571
Changes in estimates	3,823			2,896			8,537			2,539
Settlements	(2,626		)	(1,330		)	(5,311		)	(2,355		)
Balance, at end of period	$	29,366		$	15,493		$	29,366		$	15,493
Current portion included in accrued liabilities							$	8,434		$	3,589
Long-term portion							$	20,932		$	11,904

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Schedule of financial instruments that are measured at fair value on a recurring basis



	Asset Derivatives				Liability Derivatives
	September 30, 2013		December 31, 2012		September 30, 2013		December 31, 2012
Foreign currency forward contracts (Level 2)	$	94	$	—	$	863	$	268

Long-Term Debt (Tables)

9 Months Ended

Sep. 30, 2013

Long-term Debt, by Current and Noncurrent [Abstract]

Schedule of long-term debt

The Company’s long-term debt at September 30, 2013 and December 31, 2012 consists of the following (in thousands):



	September 30, 2013			December 31, 2012
Term loans	$	7,400		$	7,400
Equipment financing facility, net of unamortized discount of $47 and $94, respectively	1,893			3,661
Total debt	9,293			11,061
Less current portion	(3,432		)	(2,384		)
Long-term portion	$	5,861		$	8,677

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of summary of stock option activity

The following is a summary of stock option activity for the nine months ended September 30, 2013 (in thousands, except per share data):



	Number of Shares Outstanding		Weighted- Average Exercise Price per Share
Outstanding at December 31, 2012	8,169		$	3.28
Granted	1,417		7.15
Exercised	(773	)	1.65
Canceled	(300	)	7.73
Outstanding at September 30, 2013	8,513		3.92

Schedule of restricted stock unit activity

The following is a summary of restricted stock unit activity for the nine months ended September 30, 2013 (in thousands, except per share data):



	Restricted Stock Units		Weighted Average Fair Value per Share at Grant Date
Outstanding at December 31, 2012	248		$	5.53
Granted	285		6.92
Vested	(37	)	6.64
Canceled	(5	)	6.90
Outstanding at September 30, 2013	491		6.24

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 condensed consolidated statements of operations for the periods presented (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenues	$	137	$	62	$	309	$	119
Research and development	625		514		1,541		1,171
Sales and marketing	542		362		1,317		826
General and administrative	741		513		1,788		1,043
Total	$	2,045	$	1,451	$	4,955	$	3,159

Schedule of stock-based compensation expense by award type

The following table summarizes stock-based compensation associated with each type of award for the periods presented (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Stock options and restricted stock units	$	1,871	$	1,451	$	4,588	$	3,159
Employee Stock Purchase Plan	174		—		367		—
Total	$	2,045	$	1,451	$	4,955	$	3,159

Schedule of valuation assumptions of stock options

The following table presents the weighted-average assumptions used to estimate the fair values of the stock options granted in the periods presented:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Expected term (in years)	4.4			4.8			4.4			5.8
Expected volatility	67.2		%	78.0		%	68.7		%	74.4		%
Annual risk-free rate of return	1.2		%	0.6		%	1.0		%	0.9		%
Dividend yield	0.0		%	0.0		%	0.0		%	0.0		%
Weighted average grant date fair value	$	4.07		$	3.15		$	3.84		$	4.82

Net Loss Per Share Attributable to Common Stockholders (Tables)

9 Months Ended

Sep. 30, 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



	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012
Stock options to purchase common stock	8,493	8,180	8,095	8,420
Restricted stock units	482	132	363	268
Warrants to purchase common stock	293	331	312	331
Total	9,268	8,643	8,770	9,019

Overview and Summary of Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Apr. 04, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock, shares issued	10,315,151
Stock issued during period offering price	$ 6.00
Proceeds from issuance of common stock in IPO, net of underwriting discounts and commissions	$ 53,800	$ 0	$ 58,609
Underwriters Discounts and Commissions	3,300
Other estimated offering costs	$ 4,800
Convertible preferred stock, shares outstanding	22,220,856	0		0
Conversion of convertible preferred stock into common stock	25,171,017
Convertible notes, outstanding balance of principal and accrued paid in kind interest	$ 21,200
Conversion of notes into common stock	3,533,988
Conversion price of convertible notes	$ 6.00

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Schedule of inventory
Raw materials	$ 1,553	$ 2,223
Finished goods	22,839	17,620
Total inventory	$ 24,392	$ 19,843

Warranty Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Warranty Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Changes in the Company's product warranty liability
Balance, at beginning of period	$ 26,777	$ 11,412	$ 21,338	$ 8,738
Accruals for warranties issued during the period	1,392	2,515	4,802	6,571
Changes in estimates	3,823	2,896	8,537	2,539
Settlements	(2,626)	(1,330)	(5,311)	(2,355)
Balance, at end of period	29,366	15,493	29,366	15,493
Current portion included in accrued liabilities	8,434	3,589	8,434	3,589
Long-term portion	$ 20,932	$ 11,904	$ 20,932	$ 11,904	$ 15,260

Warranty Obligations Warranty Obligations (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Standard Product Warranty Disclosure [Abstract]
Changes in warranty accrual	$ 3,823	$ 2,896	$ 8,537	$ 2,539
Replacement cost [Member]
Standard Product Warranty Disclosure [Abstract]
Increase (decrease) in warranty expense due to changes in warranty variables estimates	400		(100)
Claim rate [Member]
Standard Product Warranty Disclosure [Abstract]
Increase (decrease) in warranty expense due to changes in warranty variables estimates			$ (4,200)
Shipping cost [Member]
Standard Product Warranty Disclosure [Abstract]
Increase (decrease) in warranty expense due to changes in warranty variables estimates		(1,900)		(1,900)
Second generation products [Member]
Standard Product Warranty Disclosure [Abstract]
Product warranty term			15 years
Second generation products [Member] \| Failure rate [Member]
Standard Product Warranty Disclosure [Abstract]
Increase (decrease) in warranty expense due to changes in warranty variables estimates	7,300	$ 4,800	$ 15,900	$ 4,400
Third generation products [Member]
Standard Product Warranty Disclosure [Abstract]
Product warranty term			25 years
Third generation products [Member] \| Failure rate [Member]
Standard Product Warranty Disclosure [Abstract]
Increase (decrease) in warranty expense due to changes in warranty variables estimates	$ (3,100)		$ (3,100)

Fair Value Measurements (Details) - Fair value, measurements, recurring [Member] - Level 2 [Member] - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Asset Derivatives
Foreign currency forward contracts (Level 2)	$ 94	$ 0
Liability Derivatives
Foreign currency forward contracts (Level 2)	$ 863	$ 268

Fair Value Measurements (Details Textual) - Not designated as hedging instrument [Member] - Foreign exchange forward [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Derivative [Line Items]
Notional amount of foreign currency	$ 20.7	$ 20.7	$ 6.1
Net loss on foreign currency	$ 0.6	$ 0.6

Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Schedule of long-term debt
Total debt	$ 9,293	$ 11,061
Less current portion	(3,432)	(2,384)
Long-term portion	5,861	8,677
Term loans [Member]
Schedule of long-term debt
Total debt	7,400	7,400
Equipment Financing Facility [Member]
Schedule of long-term debt
Total debt	1,893	3,661
Unamortized discount	$ 47	$ 94

Long-Term Debt (Details Textual)	9 Months Ended
Long-Term Debt (Details Textual)	Sep. 30, 2013 USD ($) debt_agreement
Debt Instrument [Line Items]
Number of debt agreements \| debt_agreement	3
Wells Fargo Bank [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit line facility	$ 50,000,000.0
Hercules Technology Growth Capital Inc [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Credit line facility	7,400,000.0
Debt instrument additional borrowing amount	15,600,000.0
Hercules Technology Growth Capital Inc [Member] \| Equipment Financing Facility [Member]
Debt Instrument [Line Items]
Credit line facility	$ 5,000,000.0

Stock-Based Compensation Stock Option Activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2013 $ / shares shares
Number of Shares Outstanding
Outstanding at December 31, 2012 (in shares) \| shares	8,169
Granted (in shares) \| shares	1,417
Exercised (in shares) \| shares	(773)
Canceled (in shares) \| shares	(300)
Outstanding at September 30, 2013 (in shares) \| shares	8,513
Weighted- Average Exercise Price per Share
Outstanding at December 31, 2012 (in usd per share) \| $ / shares	$ 3.28
Granted (in usd per share) \| $ / shares	7.15
Exercised (in usd per share) \| $ / shares	1.65
Canceled (in usd per share) \| $ / shares	7.73
Outstanding at September 30, 2013 (in usd per share) \| $ / shares	$ 3.92

Stock-Based Compensation Restricted Stock Unit Activity (Details) - Restricted stock units [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2013 $ / shares shares
Restricted Stock Units
Outstanding at December 31, 2012 (in shares) \| shares	248
Granted (in shares) \| shares	285
Vested (in shares) \| shares	(37)
Canceled (in shares) \| shares	(5)
Outstanding at September 30, 2013 (in shares) \| shares	491
Weighted Average Fair Value per Share at Grant Date
Outstanding at December 31, 2012 (in usd per share) \| $ / shares	$ 5.53
Granted (in usd per share) \| $ / shares	6.92
Vested (in usd per share) \| $ / shares	6.64
Canceled (in usd per share) \| $ / shares	6.90
Outstanding at September 30, 2013 (in usd per share) \| $ / shares	$ 6.24

Stock-Based Compensation Components of Stock-based Compensation Expense by Report Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	$ 2,045	$ 1,451	$ 4,955	$ 3,159
Cost of revenues [Member]
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	137	62	309	119
Research and development [Member]
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	625	514	1,541	1,171
Sales and marketing [Member]
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	542	362	1,317	826
General and administrative [Member]
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	$ 741	$ 513	$ 1,788	$ 1,043

Stock-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 2,045	$ 1,451	$ 4,955	$ 3,159
Employee stock options and restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,871	1,451	4,588	3,159
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 174	$ 0	$ 367	$ 0

Stock-Based Compensation Valuation Assumptions of Stock Options Under Black-Scholes Model (Details) - Stock options [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
The fair value of each option granted during the periods
Expected term	4 years 4 months 24 days	4 years 9 months 18 days	4 years 4 months 24 days	5 years 9 months 18 days
Expected volatility	67.20%	78.00%	68.70%	74.40%
Annual risk-free rate of return	1.20%	0.60%	1.00%	0.90%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average grant date fair value	$ 4.07	$ 3.15	$ 3.84	$ 4.82

Stock-Based Compensation (Details Textual) $ in Millions	9 Months Ended
Stock-Based Compensation (Details Textual) $ in Millions	Sep. 30, 2013 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of options exercised during period	$ 2.9
Intrinsic value of options outstanding	31.7
Total unrecognized compensation cost	$ 14.6
Weighted-average recognition period for unrecognized compensation cost	2 years 8 months 12 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of stock vested during period	$ 0.3
Intrinsic value of restricted stock units outstanding	$ 4.0

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Provision for U.S. federal or state income taxes			$ 0
Provision for income taxes related to subsidiaries located outside the U.S.	$ 141,000	$ 130,000	$ 447,000	$ 346,000

Net Loss Per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total	9,268	8,643	8,770	9,019
Stock options to purchase common stock [Member]
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total	8,493	8,180	8,095	8,420
Restricted stock units [Member]
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total	482	132	363	268
Warrants to purchase common stock [Member]
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total	293	331	312	331

Net Loss Per Share Attributable to Common Stockholders (Details Textual)	Apr. 04, 2012 shares
Stock Issuance from Initial Public Offering [Abstract]
Common stock shares issued from the IPO	10,315,151
Conversion of preferred stock into common stock (in shares)	28,700,000

Related Party Transactions (Details) - KPCB Holdings, Inc. [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]
Percentage of Company owned by related party	12.00%		12.00%
Revenue from related parties	$ 0.6	$ 0.0	$ 2.7	$ 16.8