Enphase Energy (ENPH) 10-Q 5 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Enphase Energy, Inc.
Entity Central Index Key	1,463,101
Document Type	10-Q
Document Period End Date	Jun. 30, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Current Fiscal Year End	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		44,556,907

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 31,887	$ 42,032
Accounts receivable, net of allowances of $587 and $569 at June 30, 2015 and December 31, 2014, respectively	67,315	45,119
Inventory	34,054	21,590
Prepaid expenses and other assets	8,076	6,155
Total current assets	141,332	114,896
Property and equipment, net	31,633	30,824
Goodwill	3,745	3,745
Intangibles, net	1,596	1,811
Other assets	2,992	916
Total assets	181,298	152,192
Current liabilities:
Accounts payable	34,467	22,316
Accrued liabilities	21,027	26,036
Deferred revenues, current	3,943	2,747
Warranty obligations, current (includes $1,971 and $1,125 measured at fair value at June 30, 2015 and December 31, 2014, respectively)	7,251	7,607
Borrowings under revolving credit facility	17,000	0
Total current liabilities	83,688	58,706
Long-term liabilities:
Deferred revenues, noncurrent	20,465	16,612
Warranty obligations, noncurrent (includes $3,832 and $2,437 measured at fair value at June 30, 2015 and December 31, 2014, respectively)	26,512	26,333
Other liabilities	1,885	3,589
Total liabilities	$ 132,550	$ 105,240
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; 44,427 and 43,756 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	0	0
Additional paid-in capital	217,062	208,022
Accumulated deficit	(167,914)	(160,991)
Accumulated other comprehensive loss	(400)	(79)
Total stockholders’ equity	48,748	46,952
Total liabilities and stockholders’ equity	$ 181,298	$ 152,192

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowances, accounts receivable	$ 587	$ 569
Warranty obligations, current at fair value	1,971	1,125
Warranty obligations, non-current at fair value	$ 3,832	$ 2,437
Preferred stock, par value (in usd per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	44,427,000	43,756,000
Common stock, shares outstanding (in shares)	44,427,000	43,756,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net revenues	$ 102,093	$ 82,004	$ 188,746	$ 139,584
Cost of revenues	69,066	55,172	127,695	94,097
Gross profit	33,027	26,832	61,051	45,487
Operating expenses:
Research and development	12,786	11,148	26,216	20,234
Sales and marketing	12,508	10,493	24,445	19,321
General and administrative	8,102	7,679	16,307	14,205
Total operating expenses	33,396	29,320	66,968	53,760
Loss from operations	(369)	(2,488)	(5,917)	(8,273)
Other income (expense), net:
Interest expense	(87)	(486)	(165)	(935)
Other income (expense)	79	58	(448)	165
Total other expense, net	(8)	(428)	(613)	(770)
Loss before income taxes	(377)	(2,916)	(6,530)	(9,043)
Provision for income taxes	(226)	(115)	(393)	(224)
Net loss	$ (603)	$ (3,031)	$ (6,923)	$ (9,267)
Net loss per share, basic and diluted (in usd per share)	$ (0.01)	$ (0.07)	$ (0.16)	$ (0.22)
Shares used in computing net loss per share, basic and diluted (in shares)	44,319	42,648	44,136	42,428

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (603)	$ (3,031)	$ (6,923)	$ (9,267)
Other comprehensive income (loss):
Foreign currency translation adjustments	1	6	(321)	7
Comprehensive loss	$ (602)	$ (3,025)	$ (7,244)	$ (9,260)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net loss	$ (6,923)	$ (9,267)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,054	3,902
Provision for doubtful accounts	99	711
Net loss on disposal of assets	275	28
Non-cash interest expense	80	191
Stock-based compensation	6,296	4,507
Revaluation of contingent consideration liability	(900)	0
Changes in operating assets and liabilities:
Accounts receivable	(22,295)	(15,164)
Inventory	(12,464)	856
Prepaid expenses and other assets	(4,077)	(2,272)
Accounts payable, accrued and other liabilities	6,712	16,582
Warranty obligations	(177)	2,537
Deferred revenues	5,049	1,523
Net cash (used in) provided by operating activities	(23,271)	4,134
Cash flows from investing activities:
Purchases of property and equipment	(6,260)	(4,333)
Net cash used in investing activities	(6,260)	(4,333)
Cash flows from financing activities:
Borrowings under revolving credit facility	17,000	0
Repayments of term loans	0	(2,177)
Proceeds from issuance of common stock under employee stock plans	2,744	1,701
Net cash provided by (used in) financing activities	19,744	(476)
Effect of exchange rate changes on cash	(358)	106
Net decrease in cash and cash equivalents	(10,145)	(569)
Cash and cash equivalents—Beginning of period	42,032	38,190
Cash and cash equivalents—End of period	31,887	37,621
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	$ 1,611	$ 675

OVERVIEW AND SUMMARY OF SIGNIFI

OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES 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. The Company also offers operations and maintenance services for photovoltaic (“PV”) systems including preventive and corrective maintenance, solar panel cleaning and solar system commissioning. Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the U.S, or GAAP. 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 financial statements reflect all adjustments, consisting of normal recurring items, considered necessary to present fairly the Company's financial condition, results of operations, comprehensive income (loss) and cash flows for the interim periods indicated. The results of operations for the three and six months ended June 30, 2015 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, 2014 . There have been no material changes in the Company’s significant accounting policies during the six months ended June 30, 2015 , as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 . Reference is made to the disclosures therein for a summary of all of the Company’s significant accounting policies. Use of Estimates The preparation of financial statements in conformity with GAAP 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. Significant estimates and assumptions reflected in the financial statements include revenue recognition, inventory valuation and accrued warranty obligations. 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. Recent Accounting Pronouncements Not Yet Effective In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09 (Topic 606), Revenue from Contracts with Customers, which will replace most existing revenue recognition guidance under US GAAP. The updated standard’s core principle is that revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which an entity expects to be entitled in exchange for those goods or services. The standard generally requires an entity to identify performance obligations in its contracts, estimate the amount of variable consideration to be received in the transaction price, allocate the transaction price to each separate performance obligation, and recognize revenue as obligations are satisfied. In addition, the updated standard requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. The effective date was recently deferred for one year to the interim and annual periods beginning on or after December 15, 2017. Early adoption is permitted as of the original effective date – interim and annual periods beginning on or after December 15, 2016. The guidance permits the use of either a retrospective or cumulative effect transition method. The Company has not yet selected a transition method and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures.

INVENTORY

INVENTORY	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY Inventory as of June 30, 2015 and December 31, 2014 consists of the following (in thousands): June 30, December 31, Raw materials $ 2,651 $ 3,429 Finished goods 31,403 18,161 Total inventory $ 34,054 $ 21,590

WARRANTY OBLIGATIONS

WARRANTY OBLIGATIONS	6 Months Ended
	Jun. 30, 2015
Product Warranties Disclosures [Abstract]
WARRANTY OBLIGATIONS	WARRANTY OBLIGATIONS The Company’s warranty activities during the three and six months ended June 30, 2015 and 2014 were as follows (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Warranty obligations, beginning of period $ 34,163 $ 30,728 $ 33,940 $ 30,432 Accruals for warranties issued during period 1,202 1,138 2,307 1,751 Changes in estimates 180 2,960 238 4,360 Settlements (1,715 ) (1,893 ) (2,865 ) (3,625 ) Increase due to accretion expense 210 20 371 40 Other (277 ) 16 (228 ) 11 Warranty obligations, end of period $ 33,763 $ 32,969 $ 33,763 $ 32,969 Less current portion $ (7,251 ) $ (8,477 ) Noncurrent $ 26,512 $ 24,492 For the three and six months ended June 30, 2014, warranty expense included net changes in estimates of $3.0 million and $4.4 million respectively, to reflect higher than originally estimated replacement unit costs and failure rates related to the Company’s second generation microinverter. As of June 30, 2015 , the $33.8 million in warranty obligations included $5.8 million measured at fair value (see Note 4—Fair Value Measurements).

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS 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 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. The following table presents the Company’s assets and liabilities that were measured at fair value on a recurring basis and its categorization within the fair value hierarchy at June 30, 2015 and December 31, 2014 (in thousands): Fair Value June 30, December 31, Assets: Foreign currency forward contracts Level 2 $ — $ 76 Liabilities: Foreign currency forward contracts Level 2 $ 52 $ — Warranty obligations Level 3 5,803 3,562 Contingent consideration Level 3 1,400 2,300 Derivative Instruments The Company utilizes foreign currency forward contracts from time to time to reduce the impact of foreign currency fluctuations arising from both sales and purchases denominated in Euros and the British Pound Sterling. At June 30, 2015 and December 31, 2014 , the notional amounts of the Company’s foreign currency forward contracts outstanding were $1.3 million and $1.5 million , respectively. For the six months ended June 30, 2015 and 2014 , the Company recorded net gains of $37,000 and $50,000 , respectively, related to foreign currency forward contracts in other income (expense), net. Fair Value Option for Warranty Obligations Related to 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. Under Accounting Standards Codification (“ASC”) 825—Financial Instruments, (“fair value option”), an entity may choose to elect the fair value option for such warranties at the time it first recognizes the eligible item. The Company made an irrevocable election to account for all eligible warranty obligations associated with microinverters sold since January 1, 2014 at fair value. This election was made to reflect the underlying economics of the time value of money for an obligation that will be settled over an extended period of up to 25 years. The Company estimates the fair value of warranty obligations by calculating the warranty obligations in the same manner as for sales prior to January 1, 2014 and applying an expected present value technique to that result. The expected present value technique, an income approach, converts future amounts into a single current discounted amount. In addition to the key estimates of failure rates, claim rates and replacement costs, the Company used certain Level 3 inputs which are unobservable and significant to the overall fair value measurement. Such additional assumptions included a discount rate based on the Company’s credit-adjusted risk-free rate and compensation comprised of a profit element and risk premium required of a market participant to assume the obligation. The following table provides information regarding changes in nonfinancial liabilities related to the Company’s warranty obligations measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the periods indicated (in thousands): Six Months Ended 2015 2014 Balance at beginning of period $ 3,562 $ — Accruals for warranties issued during period 2,183 1,638 Changes in estimates — 117 Settlements (85 ) — Increase due to accretion expense 371 40 Other (228 ) 11 Balance at end of period $ 5,803 $ 1,806 Contingent Consideration Liability In December 2014, the Company acquired substantially all of the assets of Next Phase Solar, Inc. In connection with the acquisition, the Company recorded a contingent consideration liability. The selling party may be entitled to receive two contingent payments, each based on achievement of defined revenue targets for the two annual periods subsequent to the acquisition date. The range of undiscounted amounts the Company could be required to pay for each contingent payment is between zero and $2.8 million . Any amounts due will be payable in early 2016 and 2017 based on achievement of defined 2015 and 2016 revenue targets, respectively. During the two-year earnout period, the Company is required to reevaluate the fair value of the contingent consideration liability at each reporting period based on any new developments and record any changes in fair value. The fair value of the contingent consideration liability was estimated by applying the income approach. That measure is based on significant Level 3 inputs not observable in the market. Key assumptions include (i) probability adjusted level of revenues and the resultant payout; and (ii) a risk-adjusted discount rate estimated using a capital asset pricing model, which reflects an expected rate of return required by a market participant holding a financial instrument with risk attributes similar to the Company’s contingent consideration liability. The following table provides information regarding changes in financial liabilities related to the contingent consideration liability measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the six months ended June 30, 2015 (in thousands): Balance—December 31, 2014 $ 2,300 Revaluations (900 ) Balance—June 30, 2015 $ 1,400 The decrease in fair value of the contingent consideration liability for the six months ended June 30, 2015 was attributable to changes in management estimates related to the probability adjusted level of revenues. The gain was recorded in sales and marketing expenses in the condensed consolidated statements of operations. Quantitative and Qualitative Information about Level 3 Fair Value Measurements As of June 30, 2015 , the significant unobservable inputs used in the fair value measurement of the Company’s liabilities designated as Level 3 are as follows: Item Measured at Fair Value Valuation Technique Description of Significant Unobservable Input Percent Used (Weighted-Average) Warranty obligations for microinverters sold since January 1, 2014 Discounted cash flows Profit element and risk premium 17% Credit-adjusted risk-free rate 19% Contingent consideration liability Probability-weighted discounted cash flows Risk-adjusted discount rate 18% Sensitivity of Level 3 Inputs Warranty Obligations Each of the significant unobservable inputs is independent of the other. The profit element and risk premium are estimated based on requirements of a third-party participant willing to assume the Company’s warranty obligations. The discount rate is determined by reference to the Company’s own credit standing at the fair value measurement date. Increasing or decreasing the profit element and risk premium input by 100 basis points would not have a material impact on the fair value measurement of the liability. Increasing the discount rate by 100 basis points would result in a $0.2 million reduction of the liability. Decreasing the discount rate by 100 basis points would result in a $0.2 million increase to the liability. Contingent Consideration Liability Changes in assumed probability adjustments with respect to achievement of target metrics can materially impact the fair value measurement of contingent consideration as of the acquisition date and for each subsequent period. Assumptions about the probability and amount of payout require less subjectivity over the course of the earnout period as management refines estimates based on actual events. Due to the short duration of the earnout period of two years , increasing or decreasing the risk-adjusted discount rate by 100 basis points would not have a material impact on the fair value measurement of the contingent consideration liability.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS June 30, 2015 December 31, 2014 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Goodwill $ 3,745 $ — $ 3,745 $ 3,745 $ — $ 3,745 Other indefinite-lived intangibles $ 286 $ — $ 286 $ 286 $ — $ 286 Intangibles assets with finite lives: Customer relationships 900 (90 ) 810 900 — 900 Patents 750 (250 ) 500 750 (125 ) 625 Total $ 1,650 $ (340 ) $ 1,310 $ 1,650 $ (125 ) $ 1,525 In July 2014, the Company purchased certain patents related to system interconnection and photovoltaic AC module construction. The patents are being amortized over their legal life of 3 years . The acquired customer relationships from the Company’s December 2014 NPS acquisition are being amortized on a straight-line basis over its estimated useful life of 5 years . For the six months ended June 30, 2015 , amortization expense related to intangible assets was $0.2 million . As of June 30, 2015 , estimated future amortization expense related to finite-lived intangible assets was as follows: Year (In thousands) 2015 (remaining 6 months) $ 215 2016 430 2017 305 2018 180 2019 180 Total $ 1,310

SHORT-TERM BORROWINGS

SHORT-TERM BORROWINGS	6 Months Ended
	Jun. 30, 2015
Short-term Debt [Abstract]
SHORT-TERM BORROWINGS	SHORT-TERM BORROWINGS The Company has a $50.0 million revolving credit facility (the “Revolver”) with Wells Fargo Bank, N.A. (“Wells Fargo”) that was entered into in November 2012 and subsequently amended in February 2014 to extend the maturity date to November 7, 2016 . The amount of credit available 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. Amounts advanced under the Revolver bear interest 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. Advances under the Revolver may be drawn, repaid and redrawn until November 7, 2016 , at which time all amounts borrowed must be repaid. The Revolver contains customary affirmative and negative covenants and events of default, and requires the Company to maintain at least $15.0 million in liquidity, consisting of cash, cash equivalents, and availability on the Revolver. Of this $15.0 million liquidity requirement, at least $5.0 million must be undrawn availability. The Company was in compliance with all financial covenants of the Revolver as of June 30, 2015 . During the second quarter of 2015, the Company borrowed $17.0 million to fund working capital requirements. As of June 30, 2015 , the Company’s net availability under the Revolver, reflecting outstanding borrowings of $17.0 million , was $22.5 million .

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2015
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

STOCK-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	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, 2014 . Equity Awards Activity Stock Options The following is a summary of stock option activity for the six months ended June 30, 2015 (in thousands, except per share data): Number of Shares Outstanding Weighted- Average Exercise Price per Share Outstanding at December 31, 2014 8,632 $ 4.75 Granted 737 11.22 Exercised (288 ) 4.34 Canceled (194 ) 10.19 Outstanding at June 30, 2015 8,887 5.18 The intrinsic value of options exercised in the six months ended June 30, 2015 was $2.4 million . As of June 30, 2015 , the intrinsic value of options outstanding was $28.8 million based on the closing price of the Company’s stock as of June 30, 2015 . Restricted Stock Units The following is a summary of restricted stock unit activity for the six months ended June 30, 2015 (in thousands, except per share data): RSUs Weighted Average Outstanding at December 31, 2014 1,345 $ 8.25 Granted 613 12.25 Vested (212 ) 7.79 Canceled (43 ) 13.13 Outstanding at June 30, 2015 1,703 9.62 The total fair value of restricted stock units that vested in the six months ended June 30, 2015 was $2.9 million . As of June 30, 2015 , the intrinsic value of restricted stock units outstanding was $13.0 million based on the closing price of the Company’s stock as of June 30, 2015 . 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 Six Months Ended 2015 2014 2015 2014 Cost of revenues $ 318 $ 194 $ 582 $ 343 Research and development 1,158 778 2,238 1,391 Sales and marketing 942 649 1,707 1,181 General and administrative 889 873 1,769 1,592 Total $ 3,307 $ 2,494 $ 6,296 $ 4,507 The following table summarizes stock-based compensation associated with stock options, restricted stock units, and employee stock purchase plan shares for the periods presented (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Stock options and restricted stock units $ 2,874 $ 2,309 $ 5,400 $ 4,148 Employee stock purchase plan 433 185 896 359 Total $ 3,307 $ 2,494 $ 6,296 $ 4,507 The following table presents the weighted-average grant date fair value of options granted for the periods presented and the assumptions used to estimate those values using a Black-Scholes option pricing model: Three Months Ended Six Months Ended 2015 2014 2015 2014 Weighted average grant date fair value $ 6.90 $ 4.24 $ 6.38 $ 4.13 Expected term (in years) 4.4 4.3 4.5 4.4 Expected volatility 72.7 % 69.5 % 72.0 % 66.4 % Annual risk-free rate of return 1.3 % 1.4 % 1.3 % 1.4 % Dividend yield 0.0 % 0.0 % 0.0 % 0.0 % 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 June 30, 2015 , there was approximately $25.9 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

INCOME TAXES	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company has used the discrete tax approach in calculating the tax expense for the three and six months ended June 30, 2015 and 2014 due to the fact that a relatively small change in the Company’s projected pre-tax net income (loss) could result in a volatile effective tax rate. Under the discrete method, the Company determines its tax (expense) benefit based upon actual results as if the interim period was an annual period. The tax provisions recorded were primarily related to income taxes in jurisdictions outside of the U.S.

NET LOSS PER SHARE

NET LOSS PER SHARE	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE The following table presents the computation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended Six Months Ended 2015 2014 2015 2014 Numerator: Net loss $ (603 ) $ (3,031 ) $ (6,923 ) $ (9,267 ) Denominator: Weighted average number of common shares outstanding 44,319 42,648 44,136 42,428 Net loss per share, basic and diluted $ (0.01 ) $ (0.07 ) $ (0.16 ) $ (0.22 ) As the Company incurred a net loss for all periods presented, potential dilutive securities from employee stock options, restricted stock units and warrants have been excluded from the diluted net loss per share computations because the effect of including such shares would have been anti-dilutive. The following table sets forth the potentially dilutive securities excluded from the computation of the diluted net loss per share (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Employee stock options 8,738 8,443 8,683 8,466 Restricted stock units 1,640 1,520 1,537 1,128 Warrants to purchase common stock 111 261 111 277 Total 10,489 10,224 10,331 9,871

OVERVIEW AND SUMMARY OF SIGNI17

OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the U.S, or GAAP. 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 financial statements reflect all adjustments, consisting of normal recurring items, considered necessary to present fairly the Company's financial condition, results of operations, comprehensive income (loss) and cash flows for the interim periods indicated. The results of operations for the three and six months ended June 30, 2015 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, 2014 .
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP 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. Significant estimates and assumptions reflected in the financial statements include revenue recognition, inventory valuation and accrued warranty obligations. 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.
Income Taxes	The Company has used the discrete tax approach in calculating the tax expense for the three and six months ended June 30, 2015 and 2014 due to the fact that a relatively small change in the Company’s projected pre-tax net income (loss) could result in a volatile effective tax rate. Under the discrete method, the Company determines its tax (expense) benefit based upon actual results as if the interim period was an annual period

INVENTORY (Tables)

INVENTORY (Tables)	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
Summary of Inventory	Inventory as of June 30, 2015 and December 31, 2014 consists of the following (in thousands): June 30, December 31, Raw materials $ 2,651 $ 3,429 Finished goods 31,403 18,161 Total inventory $ 34,054 $ 21,590

WARRANTY OBLIGATIONS (Tables)

WARRANTY OBLIGATIONS (Tables)	6 Months Ended
	Jun. 30, 2015
Product Warranties Disclosures [Abstract]
Summary of Warranty Activities	The Company’s warranty activities during the three and six months ended June 30, 2015 and 2014 were as follows (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Warranty obligations, beginning of period $ 34,163 $ 30,728 $ 33,940 $ 30,432 Accruals for warranties issued during period 1,202 1,138 2,307 1,751 Changes in estimates 180 2,960 238 4,360 Settlements (1,715 ) (1,893 ) (2,865 ) (3,625 ) Increase due to accretion expense 210 20 371 40 Other (277 ) 16 (228 ) 11 Warranty obligations, end of period $ 33,763 $ 32,969 $ 33,763 $ 32,969 Less current portion $ (7,251 ) $ (8,477 ) Noncurrent $ 26,512 $ 24,492

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the Company’s assets and liabilities that were measured at fair value on a recurring basis and its categorization within the fair value hierarchy at June 30, 2015 and December 31, 2014 (in thousands): Fair Value June 30, December 31, Assets: Foreign currency forward contracts Level 2 $ — $ 76 Liabilities: Foreign currency forward contracts Level 2 $ 52 $ — Warranty obligations Level 3 5,803 3,562 Contingent consideration Level 3 1,400 2,300
Schedule of Changes in Nonfinancial Liabilities Related to Warrant Obligations Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs	The following table provides information regarding changes in nonfinancial liabilities related to the Company’s warranty obligations measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the periods indicated (in thousands): Six Months Ended 2015 2014 Balance at beginning of period $ 3,562 $ — Accruals for warranties issued during period 2,183 1,638 Changes in estimates — 117 Settlements (85 ) — Increase due to accretion expense 371 40 Other (228 ) 11 Balance at end of period $ 5,803 $ 1,806
Summary of Changes in Financial Liabilities Related to Contingent Consideration Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs	The following table provides information regarding changes in financial liabilities related to the contingent consideration liability measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the six months ended June 30, 2015 (in thousands): Balance—December 31, 2014 $ 2,300 Revaluations (900 ) Balance—June 30, 2015 $ 1,400
Summary of Significant Unobservable Inputs used in the Fair Value Measurement of Liabilities Designated as Level 3	As of June 30, 2015 , the significant unobservable inputs used in the fair value measurement of the Company’s liabilities designated as Level 3 are as follows: Item Measured at Fair Value Valuation Technique Description of Significant Unobservable Input Percent Used (Weighted-Average) Warranty obligations for microinverters sold since January 1, 2014 Discounted cash flows Profit element and risk premium 17% Credit-adjusted risk-free rate 19% Contingent consideration liability Probability-weighted discounted cash flows Risk-adjusted discount rate 18%

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Intangible Assets	June 30, 2015 December 31, 2014 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Goodwill $ 3,745 $ — $ 3,745 $ 3,745 $ — $ 3,745 Other indefinite-lived intangibles $ 286 $ — $ 286 $ 286 $ — $ 286 Intangibles assets with finite lives: Customer relationships 900 (90 ) 810 900 — 900 Patents 750 (250 ) 500 750 (125 ) 625 Total $ 1,650 $ (340 ) $ 1,310 $ 1,650 $ (125 ) $ 1,525
Schedule of Estimated Future Amortization Expense Related to Finite-Lived Intangible Assets	For the six months ended June 30, 2015 , amortization expense related to intangible assets was $0.2 million . As of June 30, 2015 , estimated future amortization expense related to finite-lived intangible assets was as follows: Year (In thousands) 2015 (remaining 6 months) $ 215 2016 430 2017 305 2018 180 2019 180 Total $ 1,310

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	The following is a summary of stock option activity for the six months ended June 30, 2015 (in thousands, except per share data): Number of Shares Outstanding Weighted- Average Exercise Price per Share Outstanding at December 31, 2014 8,632 $ 4.75 Granted 737 11.22 Exercised (288 ) 4.34 Canceled (194 ) 10.19 Outstanding at June 30, 2015 8,887 5.18
Summary of Restricted Stock Unit Activity	The following is a summary of restricted stock unit activity for the six months ended June 30, 2015 (in thousands, except per share data): RSUs Weighted Average Outstanding at December 31, 2014 1,345 $ 8.25 Granted 613 12.25 Vested (212 ) 7.79 Canceled (43 ) 13.13 Outstanding at June 30, 2015 1,703 9.62
Summary of the Components of Total Stock-Based Compensation Expense	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 Six Months Ended 2015 2014 2015 2014 Cost of revenues $ 318 $ 194 $ 582 $ 343 Research and development 1,158 778 2,238 1,391 Sales and marketing 942 649 1,707 1,181 General and administrative 889 873 1,769 1,592 Total $ 3,307 $ 2,494 $ 6,296 $ 4,507
Summary of Stock-Based Compensation Associated with Each Type of Award	The following table summarizes stock-based compensation associated with stock options, restricted stock units, and employee stock purchase plan shares for the periods presented (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Stock options and restricted stock units $ 2,874 $ 2,309 $ 5,400 $ 4,148 Employee stock purchase plan 433 185 896 359 Total $ 3,307 $ 2,494 $ 6,296 $ 4,507
Summary of the Weighted-Average Grant Date Fair Value of Options Granted	The following table presents the weighted-average grant date fair value of options granted for the periods presented and the assumptions used to estimate those values using a Black-Scholes option pricing model: Three Months Ended Six Months Ended 2015 2014 2015 2014 Weighted average grant date fair value $ 6.90 $ 4.24 $ 6.38 $ 4.13 Expected term (in years) 4.4 4.3 4.5 4.4 Expected volatility 72.7 % 69.5 % 72.0 % 66.4 % Annual risk-free rate of return 1.3 % 1.4 % 1.3 % 1.4 % Dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table presents the computation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended Six Months Ended 2015 2014 2015 2014 Numerator: Net loss $ (603 ) $ (3,031 ) $ (6,923 ) $ (9,267 ) Denominator: Weighted average number of common shares outstanding 44,319 42,648 44,136 42,428 Net loss per share, basic and diluted $ (0.01 ) $ (0.07 ) $ (0.16 ) $ (0.22 )
Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Net Loss Per Share	The following table sets forth the potentially dilutive securities excluded from the computation of the diluted net loss per share (in thousands): Three Months Ended Six Months Ended 2015 2014 2015 2014 Employee stock options 8,738 8,443 8,683 8,466 Restricted stock units 1,640 1,520 1,537 1,128 Warrants to purchase common stock 111 261 111 277 Total 10,489 10,224 10,331 9,871

INVENTORY - Summary of Inventor

INVENTORY - Summary of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of inventory
Raw materials	$ 2,651	$ 3,429
Finished goods	31,403	18,161
Total inventory	$ 34,054	$ 21,590

WARRANTY OBLIGATIONS - Summary

WARRANTY OBLIGATIONS - Summary of Warranty Activities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Changes in the Company's product warranty liability
Warranty obligations, beginning of period	$ 34,163	$ 30,728	$ 33,940	$ 30,432
Accruals for warranties issued during period	1,202	1,138	2,307	1,751
Changes in estimates	180	2,960	238	4,360
Settlements	(1,715)	(1,893)	(2,865)	(3,625)
Increase due to accretion expense	210	20	371	40
Other	(277)	16	(228)	11
Warranty obligations, end of period	$ 34,163	$ 30,728	$ 33,940	$ 30,432	$ 33,763	$ 33,940	$ 32,969
Less current portion					(7,251)	(7,607)	(8,477)
Noncurrent					$ 26,512	$ 26,333	$ 24,492

WARRANTY OBLIGATIONS - Narrativ

WARRANTY OBLIGATIONS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Product Warranty Liability [Line Items]
Changes in warranty estimates	$ 180	$ 2,960	$ 238	$ 4,360
Warranty obligations, end of period	33,763	32,969	33,763	32,969	$ 34,163	$ 33,940	$ 30,728	$ 30,432
Recurring | Warranty obligations for microinverters sold since January 1, 2014 | Level 3
Product Warranty Liability [Line Items]
Fair value liabilities	$ 5,803	$ 1,806	$ 5,803	$ 1,806		$ 3,562		$ 0

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Level 2
Assets:
Foreign currency forward contracts	$ 0	$ 76
Liabilities:
Foreign currency forward contracts	52	0
Level 3 | Warranty obligations
Liabilities:
Fair value liabilities	5,803	3,562	$ 1,806	$ 0
Level 3 | Contingent consideration
Liabilities:
Fair value liabilities	$ 1,400	$ 2,300

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details)	6 Months Ended
	Jun. 30, 2015USD ($)	Jun. 30, 2014USD ($)	Dec. 31, 2014USD ($)payment
Derivative [Line Items]
Contingent consideration earnout period	2 years
Discounted cash flows | Recurring | Level 3 | Contingent consideration
Derivative [Line Items]
Decrease to fair value measurement as a result of 100 basis point increase	$ 200,000
Increase to fair value measurement as a result of 100 basis point decrease	200,000
Next Phase Solar, Inc.
Derivative [Line Items]
Number of contingent payments | payment			2
Contingent payment, low range of undiscounted amounts			$ 0
Contingent payment, high range of undiscounted amounts			2,800,000
Not designated as hedging instrument | Foreign exchange forward
Derivative [Line Items]
Notional amount of foreign currency	1,300,000		$ 1,500,000
Net gain on foreign currency	$ 37,000	$ 50,000

FAIR VALUE MEASUREMENTS - Sch29

FAIR VALUE MEASUREMENTS - Schedule of Changes in Nonfinancial Liabilities Related to Warrant Obligations Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - Level 3 - Recurring - Warranty obligations - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 3,562	$ 0
Accruals for warranties issued during period	2,183	1,638
Changes in estimates	0	117
Settlements	(85)	0
Increase due to accretion expense	371	40
Other	(228)	11
Balance at end of period	$ 5,803	$ 1,806

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of Changes in Financial Liabilities Related to Contingent Consideration Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - Next Phase Solar, Inc. - Contingent consideration - Recurring - Level 3 $ in Thousands	6 Months Ended
	Jun. 30, 2015USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 2,300
Revaluations	(900)
Balance at end of period	$ 1,400

FAIR VALUE MEASUREMENTS - Sum31

FAIR VALUE MEASUREMENTS - Summary of Significant Unobservable Inputs used in the Fair Value Measurement of Liabilities Designated as Level 3 (Details) - Discounted cash flows - Recurring - Level 3	6 Months Ended
	Jun. 30, 2015
Warranty obligations for microinverters sold since January 1, 2014
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Profit element and risk premium	17.00%
Credit-adjusted risk-free rate	19.00%
Contingent consideration liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-adjusted discount rate	18.00%

GOODWILL AND INTANGIBLE ASSET32

GOODWILL AND INTANGIBLE ASSETS - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill, gross	$ 3,745	$ 3,745
Goodwill	3,745	3,745
Other indefinite-lived intangibles	286	286
Intangibles assets with finite lives:
Intangibles assets with finite lives, gross	1,650	1,650
Intangibles assets with finite lives, accumulated amortization	(340)	(125)
Total	1,310	1,525
Customer relationships
Intangibles assets with finite lives:
Intangibles assets with finite lives, gross	900	900
Intangibles assets with finite lives, accumulated amortization	(90)	0
Total	810	900
Patents
Intangibles assets with finite lives:
Intangibles assets with finite lives, gross	750	750
Intangibles assets with finite lives, accumulated amortization	(250)	(125)
Total	$ 500	$ 625

GOODWILL AND INTANGIBLE ASSET33

GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended
	Dec. 31, 2014	Jul. 31, 2014	Jun. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense related to intangible assets			$ 0.2
Patents
Finite-Lived Intangible Assets [Line Items]
Useful life		3 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years

GOODWILL AND INTANGIBLE ASSET34

GOODWILL AND INTANGIBLE ASSETS - Schedule of Estimated Future Amortization Expense Related to Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2015 (remaining 6 months)	$ 215
2,016	430
2,017	305
2,018	180
2,019	180
Total	$ 1,310	$ 1,525

SHORT-TERM BORROWINGS - Narrati

SHORT-TERM BORROWINGS - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Feb. 28, 2014	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Short-term Debt [Line Items]
Borrowings under revolving credit facility			$ 17,000,000	$ 0
Outstanding borrowings		$ 17,000,000	17,000,000		$ 0
Line of credit | Wells Fargo Bank | Revolving credit facility
Short-term Debt [Line Items]
Credit line facility	$ 50,000,000
Amount of liquidity required for debt compliance	15,000,000
Amount of undrawn credit for debt compliance	$ 5,000,000
Borrowings under revolving credit facility		17,000,000
Outstanding borrowings		17,000,000	17,000,000
Remaining borrowing capacity		$ 22,500,000	$ 22,500,000
Line of credit | Wells Fargo Bank | Revolving credit facility | LIBOR | Minimum
Short-term Debt [Line Items]
Basis spread on variable rate	1.50%
Line of credit | Wells Fargo Bank | Revolving credit facility | LIBOR | Maximum
Short-term Debt [Line Items]
Basis spread on variable rate	4.25%

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of Stock Option Activity (Details) - 6 months ended Jun. 30, 2015 - $ / shares shares in Thousands	Total
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	8,632
Granted (in shares)	737
Exercised (in shares)	(288)
Canceled (in shares)	(194)
Outstanding, ending balance (in shares)	8,887
Weighted- Average Exercise Price per Share
Outstanding, beginning balance (in usd per share)	$ 4.75
Granted (in usd per share)	11.22
Exercised (in usd per share)	4.34
Canceled (in usd per share)	10.19
Outstanding, ending balance (in usd per share)	$ 5.18

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised during period	$ 2.4
Intrinsic value of options outstanding	28.8
Total unrecognized compensation cost	$ 25.9
Weighted-average recognition period for unrecognized compensation cost	2 years 8 months 12 days
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of stock vested during period	$ 2.9
Intrinsic value of restricted stock units outstanding	$ 13

STOCK-BASED COMPENSATION - Su38

STOCK-BASED COMPENSATION - Summary of Restricted Stock Unit Activity (Details) - 6 months ended Jun. 30, 2015 - Restricted stock units - $ / shares shares in Thousands	Total
RSUs
Outstanding, beginning balance (in shares)	1,345
Granted (in shares)	613
Vested (in shares)	(212)
Canceled (in shares)	(43)
Outstanding, ending balance (in shares)	1,703
Weighted Average Fair Value per Share at Grant Date
Outstanding, beginning balance (in usd per share)	$ 8.25
Granted (in usd per share)	12.25
Vested (in usd per share)	7.79
Canceled (in usd per share)	13.13
Outstanding, ending balance (in usd per share)	$ 9.62

STOCK-BASED COMPENSATION - Su39

STOCK-BASED COMPENSATION - Summary of the Components of Total Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	$ 3,307	$ 2,494	$ 6,296	$ 4,507
Cost of revenues
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	318	194	582	343
Research and development
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	1,158	778	2,238	1,391
Sales and marketing
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	942	649	1,707	1,181
General and administrative
Allocation of Stock-based Compensation Expense Included in the Consolidated Statement of Operations [Abstract]
Total stock-based compensation expense	$ 889	$ 873	$ 1,769	$ 1,592

STOCK-BASED COMPENSATION - Su40

STOCK-BASED COMPENSATION - Summary of Stock-Based Compensation Associated with Each Type of Award (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 3,307	$ 2,494	$ 6,296	$ 4,507
Stock options and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,874	2,309	5,400	4,148
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 433	$ 185	$ 896	$ 359

STOCK-BASED COMPENSATION - Su41

STOCK-BASED COMPENSATION - Summary of the Weighted-Average Grant Date Fair Value of Options Granted (Details) - Stock options - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
The fair value of each option granted during the periods
Weighted average grant date fair value (in usd per share)	$ 6.90	$ 4.24	$ 6.38	$ 4.13
Expected term (in years)	4 years 4 months 24 days	4 years 3 months 19 days	4 years 6 months	4 years 4 months 24 days
Expected volatility	72.70%	69.50%	72.00%	66.40%
Annual risk-free rate of return	1.30%	1.40%	1.30%	1.40%
Dividend yield	0.00%	0.00%	0.00%	0.00%

NET LOSS PER SHARE - Schedule o

NET LOSS PER SHARE - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net loss	$ (603)	$ (3,031)	$ (6,923)	$ (9,267)
Denominator:
Weighted average number of common shares outstanding (in shares)	44,319	42,648	44,136	42,428
Net loss per share, basic and diluted (in usd per share)	$ (0.01)	$ (0.07)	$ (0.16)	$ (0.22)

NET LOSS PER SHARE - Schedule43

NET LOSS PER SHARE - Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total (in shares)	10,489	10,224	10,331	9,871
Employee stock options
The potential common shares outstanding that were excluded from the computation of diluted net loss per share attributable to common stockholders
Total (in shares)	8,738	8,443	8,683	8,466
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 (in shares)	1,640	1,520	1,537	1,128
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 (in shares)	111	261	111	277