Itron Networked Solutions (SSNI) 10-K 27 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 21, 2014	Jun. 28, 2013
Document And Entity Information [Abstract]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'SSNI	'	'
Entity Registrant Name	'SILVER SPRING NETWORKS INC	'	'
Entity Central Index Key	'0001180079	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Non-accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	47,752,042	'
Entity Public Float	'	'	$636

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$82,596	$72,646
Short-term investments	63,256	'
Accounts receivable	69,724	56,528
Inventory	4,350	7,731
Deferred cost of revenue	37,460	45,298
Prepaid expenses and other current assets	4,758	3,456
Total current assets	262,144	185,659
Property and equipment, net	12,364	12,701
Deferred cost of revenue, non-current	238,663	199,865
Deferred tax assets, non-current	1,613	8,265
Other long-term assets	1,567	11,254
Total assets	516,351	417,744
Current liabilities:	'	'
Accounts payable	31,317	28,104
Accrued liabilities	21,282	14,831
Deferred revenue	111,293	89,838
Current portion of capital lease obligations	1,615	1,647
Deferred tax liability	1,176	7,897
Total current liabilities	166,683	142,317
Deferred revenue, non-current	413,360	418,218
Preferred stock warrant liability	'	11,261
Convertible promissory notes and embedded derivatives	'	56,319
Other liabilities	14,426	18,412
Commitments and contingencies (Note 6)	'	'
Convertible preferred stock: $0.001 par value; no shares authorized, issued and outstanding, and aggregate liquidation preference of $0 as of December 31, 2013; 26,072 shares authorized, 22,366 shares issued and outstanding, and aggregate liquidation preference of $381,338 as of December 31, 2012	'	270,725
Stockholders' deficit:	'	'
Preferred stock, $0.001 par value, 10,000 shares authorized and no shares issued or outstanding as of December 31, 2013; no shares authorized, issued or outstanding, as of December 31, 2012	'	'
Common stock, $0.001 par value; 1,000,000 shares authorized and 47,384 shares issued and outstanding as of December 31, 2013; 80,000 shares authorized and 3,764 shares issued and outstanding as of December 31, 2012	46	4
Additional paid-in capital	538,967	51,078
Accumulated other comprehensive income (loss)	130	-136
Accumulated deficit	-617,261	-550,454
Total stockholders' deficit	-78,118	-499,508
Total liabilities, convertible preferred stock and stockholders' deficit	$516,351	$417,744

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	1,000,000,000	80,000,000
Common stock, shares issued	47,384,000	3,764,000
Common stock, shares outstanding	47,384,000	3,764,000
Convertible preferred stock [Member]	'	'
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	0	26,072,000
Preferred stock, shares issued	0	22,366,000
Preferred stock, shares outstanding	0	22,366,000
Preferred stock, aggregate liquidation preference	$0	$381,338

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'
Product revenue	$224,310	$162,623	$212,317
Service revenue	102,548	34,114	24,733
Total revenue, net	326,858	196,737	237,050
Cost of revenue:	'	'	'
Product cost of revenue	150,315	115,325	166,053
Service cost of revenue	61,189	49,693	48,046
Total cost of revenue	211,504	165,018	214,099
Gross profit	115,354	31,719	22,951
Operating expenses:	'	'	'
Research and development	77,018	61,998	57,510
Sales and marketing	34,931	29,104	25,221
General and administrative	45,160	29,261	34,353
Legal settlements and amortization of acquired intangibles	'	'	1,097
Total operating expenses	157,109	120,363	118,181
Operating loss	-41,755	-88,644	-95,230
Other income (expense), net:	'	'	'
Interest income	86	4	15
Interest expense	-1,199	-4,296	-343
Other income (loss), net	-39	-269	46
Conversion of promissory notes and remeasurement of warrants and derivatives	-23,676	3,878	3,516
Other income (expense), net	-24,828	-683	3,234
Loss before income taxes	-66,583	-89,327	-91,996
Provision for income taxes	224	390	363
Net loss	-66,807	-89,717	-92,359
Deemed dividend to convertible preferred stockholders	-105,000	'	'
Net loss attributable to common stockholders	($171,807)	($89,717)	($92,359)
Net loss per share	'	'	'
Basic and diluted	($4.54)	($24.45)	($26.07)
Weighted average shares used to compute net loss per share	'	'	'
Basic and diluted	37,877	3,670	3,543

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]	'	'	'
Net loss	($66,807)	($89,717)	($92,359)
Other comprehensive income (loss):	'	'	'
Change in foreign currency translation adjustment	182	-119	-51
Net unrealized holding gain (loss) on available for sale investments (net of tax effect of $51, $0, and $0)	84	'	-14
Other comprehensive income (loss)	266	-119	-65
Comprehensive loss	($66,541)	($89,836)	($92,424)

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Loss (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]	'	'	'
Net unrealized holding gain (loss) on available for sale investments, tax	$51	$0	$0

Consolidated_Statements_of_Con

Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (USD $)	Total	Convertible preferred stock [Member]	Common stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]
In Thousands, except Share data
Beginning Balance at Dec. 31, 2010	($351,047)	$270,725	$4	$17,279	$48	($368,378)
Beginning Balance, shares at Dec. 31, 2010	'	22,366,000	3,476,000	'	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock	810	'	'	810	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock, shares	'	'	131,000	'	'	'
Repurchases and forfeitures of common and restricted stock	-29	'	'	-29	'	'
Repurchases and forfeitures of common and restricted stock, shares	'	'	-5,000	'	'	'
Retirement of common stock	'	'	'	'	'	'
Retirement of common stock, shares	'	'	-2,000	'	'	'
Stock-based compensation	14,820	'	'	14,820	'	'
Issuance of common stock warrant	2,512	'	'	2,512	'	'
Other comprehensive income (loss)	-65	'	'	'	-65	'
Net loss	-92,359	'	'	'	'	-92,359
Ending Balance at Dec. 31, 2011	-425,358	270,725	4	35,392	-17	-460,737
Ending Balance, shares at Dec. 31, 2011	'	22,366,000	3,600,000	'	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock	831	'	'	831	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock, shares	'	'	179,000	'	'	'
Repurchases and forfeitures of common and restricted stock	-237	'	'	-237	'	'
Repurchases and forfeitures of common and restricted stock, shares	'	'	-15,000	'	'	'
Stock-based compensation	15,092	'	'	15,092	'	'
Other comprehensive income (loss)	-119	'	'	'	-119	'
Net loss	-89,717	'	'	'	'	-89,717
Ending Balance at Dec. 31, 2012	-499,508	270,725	4	51,078	-136	-550,454
Ending Balance, shares at Dec. 31, 2012	'	22,366,000	3,764,000	'	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock	2,926	'	1	2,926	'	'
Issuance of common stock upon exercise of stock options and vesting of restricted stock, shares	'	'	1,644,000	'	'	'
Shares withheld related to net share settlement of restricted stock	-8,019	'	'	-8,019	'	'
Shares withheld related to net share settlement of restricted stock, shares	'	'	-422,000	'	'	'
Discount on Series E preferred stock	105,000	-105,000	'	105,000	'	'
Deemed dividend to Series E preferred stock	-105,000	105,000	'	-105,000	'	'
Conversion of preferred stock to common stock	270,725	-270,725	32	270,693	'	'
Conversion of preferred stock to common stock , shares	32,406,995	-22,366,000	32,407,000	'	'	'
Conversion of preferred stock warrants to common stock warrants	66	'	'	66	'	'
Conversion of preferred stock warrants to common stock warrants, shares	'	'	'	'	'	'
Conversion of convertible promissory notes	79,441	'	3	79,437	'	'
Conversion of convertible promissory notes, shares	'	'	3,765,000	'	'	'
Issuance of common stock from private placement	12,000	'	1	11,999	'	'
Issuance of common stock from private placement, shares	'	'	706,000	'	'	'
Issuance of common stock from initial public offering, net of offering costs	79,921	'	5	79,916	'	'
Issuance of common stock from initial public offering, net of offering costs, shares	'	'	5,463,000	'	'	'
Issuance of common stock upon net exercise of common stock warrants	'	'	'	'	'	'
Issuance of common stock upon net exercise of common stock warrants, shares	'	'	57,000	'	'	'
Stock-based compensation	50,871	'	'	50,871	'	'
Other comprehensive income (loss)	266	'	'	'	266	'
Net loss	-66,807	'	'	'	'	-66,807
Ending Balance at Dec. 31, 2013	($78,118)	'	$46	$538,967	$130	($617,261)
Ending Balance, shares at Dec. 31, 2013	'	'	47,384,000	'	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flow (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows provided by (used in) operating activities:	'	'	'
Net loss	($66,807)	($89,717)	($92,359)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:	'	'	'
Depreciation and amortization	6,646	7,255	6,958
Stock-based compensation	52,504	15,092	14,820
Fair value of common stock warrants issued	'	'	2,512
Conversion of promissory notes and remeasurement of warrants and derivatives	23,676	-3,878	-3,516
Provision for inventory obsolescence	430	1,202	89
Non-cash interest expense on convertible notes	935	1,461	'
Other non-cash adjustments	63	358	133
Changes in operating assets and liabilities:	'	'	'
Accounts receivable	-13,245	-23,177	3,684
Inventory	2,951	-6,448	2,847
Prepaid expenses and other current assets	-1,153	1,109	-600
Deferred cost of revenue	-30,960	-38,860	51,191
Other long-term assets	4,504	-3,446	-2,890
Accounts payable	2,848	10,883	-8,514
Accrued liabilities	4,728	-3,191	2,393
Customer deposits	-61	-7,046	-5,204
Deferred revenue	16,597	107,596	-921
Other liabilities	-3,642	6,529	885
Net cash provided by (used) in operating activities	14	-24,278	-28,492
Cash flows provided by (used in) investing activities:	'	'	'
Decrease in restricted cash	'	140	13,921
Proceeds from sales and maturities of short-term investments	9,122	'	25,000
Purchases of short-term investments	-72,339	'	'
Purchases of property and equipment	-3,950	-4,854	-4,088
Net cash provided by (used in) investing activities	-67,167	-4,714	34,833
Cash flows provided by (used in) financing activities:	'	'	'
Payment upon termination of preferred stock warrants of a related party	-12,000	'	'
Proceeds from initial public offering, net of offering costs	84,247	'	'
Proceeds from private placement of common stock with a related party	12,000	'	'
Payments on capital lease obligations	-2,034	-1,312	-2,182
Proceeds from sale-leaseback of property and equipment	'	1,676	'
Proceeds from issuance of convertible promissory note	'	28,993	24,000
Proceeds from issuance of common stock, net of repurchases	2,909	594	781
Taxes paid related to net share settlement of equity awards	-8,019	'	'
Net cash provided by (used in) financing activities	77,103	29,951	22,599
Net increase (decrease) in cash and cash equivalents	9,950	959	28,940
Cash and cash equivalents-beginning of period	72,646	71,687	42,747
Cash and cash equivalents-end of period	82,596	72,646	71,687
Supplemental cash flow information-cash paid for taxes	233	801	437
Supplemental cash flow information-cash paid for interest	263	427	187
Non-cash investing and financing activities:	'	'	'
Conversion of convertible preferred stock into common stock	270,725	'	'
Fair value of common stock issued on conversion of convertible promissory notes	79,441	'	'
Deferred offering costs not yet paid	20	'	'
Property and equipment acquired under capital lease	$1,767	$2,915	$407

Description_of_Business_and_Su

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Description of Business and Summary of Significant Accounting Policies	'
	1. DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	We have over ten years of experience creating, building and successfully deploying large scale networks and solutions enabling the “internet of things” for critical infrastructure. The “internet of things” refers to a system where a diversity of physical devices have the capacity to communicate using internet technologies. Our first area of focus was in energy, creating a leading grid network by applying advanced networking technology and solutions to the power grid. We have recently broadened beyond the smart grid to networking other critical infrastructure such as street lights, enabling smarter and more efficient cities.
	We provide a networking platform and solutions that enable utilities to transform the power grid infrastructure into the smart grid. The foundation of our technology is a standards-based and secure Internet Protocol, or IP, network. Our networking platform provides two-way communications between the utility back office and devices on the power grid. In addition to our networking platform, we offer a suite of solutions that run on top of our network and complementary services. Our solutions include advanced metering, distribution automation and demand-side management. Our service offerings include professional services to implement our products, managed services and software as a service, or SaaS, to assist utilities with managing the network and solutions, and ongoing customer support.
	We believe our technology is particularly well suited for a range of other solutions across the broad category of “internet of things.” We are focused on critical infrastructure that requires similar networking performance as the current market we serve. Our first expansion beyond the power grid has been on city infrastructure, specifically networking street lights. We believe that by applying advanced networking technology, we can enable cities to achieve their goals for increasing energy and operating efficiency while improving quality of life. We expect to expand our offerings in this area as the market opportunity evolves.
	Silver Spring Networks, Inc., headquartered in Redwood City, California, was founded in July 2002 and was incorporated in the State of Delaware on July 3, 2002 as Real Time Techcomm, Inc. On August 6, 2002, we changed our name to Silver Spring Networks, Inc.
	Reverse Stock Split
	Prior to our Initial Public Offering (“IPO”), our Board of Directors and holders of the requisite number of outstanding shares of our capital stock approved an amendment to our restated certificate of incorporation to effect a 5-for-1 reverse stock split of our outstanding capital stock. The reverse stock split was effected on February 11, 2013. The reverse stock split did not result in an adjustment to par value. The reverse stock split is reflected in the accompanying consolidated financial statements and related notes on a retroactive basis for all periods presented.
	Initial Public Offering
	In March 2013, we completed our IPO in which we issued and sold 5,462,500 shares of common stock at a public offering price of $17.00 per share. We received net proceeds of $84.2 million after deducting underwriting discounts and commissions of $6.5 million and paid offering costs in the year ended December 31, 2013 of $2.2 million, but before deducting previously paid offering expenses of approximately $4.2 million. Concurrently with our IPO, we issued and sold in a private placement 705,881 shares of common stock at the public offering price of $17.00 per share, which resulted in net proceeds of $12.0 million. In addition, in connection with our IPO:
		•		All of our outstanding convertible preferred stock converted into 32,406,995 shares of common stock.
		•		Our $24.0 million and $30.0 million convertible notes together with contractual accrued interest of $2.3 million converted into 3,764,954 shares of common stock. In connection with the conversion, we recorded a loss on debt extinguishments of $22.9 million. Please see Note 5 Borrowings for further discussion on the conversion features of the convertible notes, the calculation of the number of shares into which the notes were converted and the accounting for debt extinguishment.
		•		We reduced our preferred stock warrant liability by $11.2 million and recorded a loss of $0.8 million in the year ended December 31, 2013 resulting from our payment of $12.0 million as consideration for the termination of certain warrants to purchase shares of Series A preferred stock and all warrants to purchase shares of Series C preferred stock, which occurred immediately prior to the effectiveness of our IPO. Please see Note 7 Convertible Preferred Stock and Preferred Stock Warrants.
		•		We reclassified the preferred stock warrant liability for the surviving warrant to purchase shares of Series A preferred stock and all warrants to purchase shares of Series E preferred stock to additional paid-in capital, as these warrants converted to warrants to purchase shares of common stock. Please see Note 7 Convertible Preferred Stock and Preferred Stock Warrants.
		•		We recognized stock-based compensation expense of $4.4 million in the year ended December 31, 2013 upon the issuance of 87,507 shares of common stock following the vesting upon the effectiveness of the Registration Statement on Form S-1 of 87,507 restricted stock units previously granted in connection with our incentive bonus plans. Please see below—Corporate Bonus Incentive Plan for further discussion of this stock-based compensation expense.
		•		We recognized stock-based compensation expense of $10.2 million in the year ended December 31, 2013 upon the issuance of 602,274 shares of common stock following the granting upon the effectiveness of the Registration Statement on Form S-1 of 602,274 fully vested restricted stock units in connection with our incentive bonus plans. Please see below—Corporate Bonus Incentive Plan for further discussion of this stock-based compensation expense.
		•		We recognized stock-based compensation expense of approximately $4.7 million in the year ended December 31, 2013 related to the modification of stock options held by current employees. Please see Note 9 Stock-Based Compensation for further discussion of this stock-based compensation expense.
		•		We reclassified $6.4 million of deferred issuance costs previously recorded in other long-term assets as an off-set to the equity proceeds in connection with our IPO.
	Accounting Principles and Basis of Presentation
	The consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP. The consolidated financial statements include the accounts of Silver Spring Networks, Inc. and its wholly owned subsidiaries. Intercompany balances and transactions have been eliminated in consolidation.
	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, contingent assets and liabilities, and revenue and expenses during the reporting period. Estimates are used for revenue and cost recognition, inventory valuation, warranty obligations, preferred stock warrants and embedded derivatives valuations, stock-based compensation, classification of current and non-current deferred revenue and deferred cost of revenue, income taxes and deferred income tax assets and associated valuation allowances. These estimates generally involve complex issues and require judgments, involve the analysis of historical and prediction of future trends, can require extended periods of time to resolve and are subject to change from period to period. Actual results may differ materially from management’s estimates.
	Cash, Cash Equivalents and Short-term Investments
	Cash equivalents consist of highly liquid investments with insignificant interest rate risk and original or remaining maturities at the time of purchase of three months or less, and consist of money market funds. Short-term investments consist of high investment grade securities with original or remaining maturities at the time of purchase of greater than three months, and are available for use in current operations. We classify all of our cash equivalents and short-term investments as available-for-sale, which are recorded at fair value. Unrealized gains and losses are included in accumulated other comprehensive income (loss) in stockholders’ deficit. Realized gains and losses are included in other income and expense, net. Determining whether a decline in fair value is other-than-temporary requires management judgment based on the specific facts and circumstances of each security. We evaluate our short-term investments for impairment each reporting period. Amounts are reclassified out of accumulated other comprehensive income (loss) into earnings using the specific identification method.
	Inventory
	Inventory is stated at the lower of cost or market. Cost is computed using standard cost, which approximates actual cost on a first-in, first-out basis. The determination of market value involves numerous judgments including estimated average selling prices based upon recent sales volumes, industry trends, existing customer orders and current contract prices. We evaluate our ending inventories for excess quantities and obsolescence based on forecasted demand within specific time horizons, technological obsolescence, and an assessment of any inventory that is not of saleable condition. Forecasted demand requires management estimates and is subject to several uncertainties including market and economic conditions, technology changes and new product introductions. Actual demand may differ from forecasted demand, and such differences may have a material effect on recorded inventory values and operating results.
	In addition, we enter into purchase commitments with third-party contract manufacturers to manage lead times and meet product forecasts and with other parties to purchase various key components used in the manufacture of our products. Accruals are established for estimated losses on purchased components for which we believe it is probable that they will not be recoverable in future operations. To the extent that such forecasts are not achieved, commitments and associated accruals may change.
	Revenue Recognition
	We generally market our products and services for our advanced metering, distribution automation and demand-side management solutions directly to customers. For our advanced metering solution, we contract with third-party device manufacturers, which integrate our communications modules into their meters. Our advanced metering solution, which includes our UtilOS network operating system, UtilityIQ software suite, networking hardware, and communications modules, provides utilities with two-way communication from our communications modules to the utility’s back office. Our hardware devices include UtilOS embedded software, which functions together with the tangible hardware elements to deliver the tangible products’ essential functionality. Our UtilityIQ software suite of products includes software that is not embedded with the tangible hardware elements, but that is also necessary to deliver the tangible products’ essential network functionality, as well as other application software that provides additional functionality to the network solution. We derive revenue from sales of products, including hardware and software, as well as services, including network design and deployment support, managed services and SaaS, and ongoing customer support. We enter into separate arrangements with third party device manufacturers to integrate our communications modules with their meters pursuant to our customers’ specifications. While we may receive payment directly from these third party device manufacturers, the timing of revenue recognition related to communications modules delivered to third party device manufacturers is ultimately determined based upon acceptance by our customers. Substantially all of our sales of communications modules have been fulfilled through third party device manufacturers in this manner.
	We enter into multiple deliverable arrangements with customers to deploy our networking platform and solutions, which include the delivery of hardware and software, as well as services.
	Judgment is required in determining the separate units of accounting, which depends on whether the delivered items have standalone value to customers. When we sell or could sell our products and services separately, or when the customer could resell them on a standalone basis, we treat the delivered elements as having standalone value. In our typical customer arrangements, we consider the following to be separate units of accounting: our hardware together with the related embedded software; our network management software; and our service offerings, which include professional services, managed services and SaaS, and ongoing customer support.
	We determine total arrangement consideration, and exclude amounts that are contingent upon the delivery of additional items or meeting other specified performance conditions, including potential refunds or penalty provisions. We allocate the total arrangement consideration to the deliverables based on our determination of the units of accounting and their relative selling prices. As we have not yet established vendor-specific objective evidence or VSOE or identified third-party evidence of fair value for these units of accounting, we use our best estimate of selling price to perform the relative fair value allocation. Judgment is also required in determining how to measure and allocate arrangement consideration among the separate units of accounting. The process for performing an assessment of our best estimate of selling price for our products and services is based on quantitative and qualitative aspects of multiple factors. These factors include market conditions, such as competitive alternatives and pricing practices, as well as company-specific factors, such as standalone sales, nature and size of the customer, contractually stated prices, costs to manufacture products or provide services and profit objectives. In establishing such profit objectives, we consider prices in previous contracts, size of the transaction, and the drivers, if any, that could influence future margins.
	The following revenue recognition criteria are applied to the units of accounting in all utility customer arrangements, as well as those in which orders of communications modules are fulfilled through third party device manufacturers as described above. We do not recognize revenue for a unit of accounting until all of the following criteria have been met:
		•		Persuasive evidence of an arrangement exists. Binding contracts or purchase orders are used to determine the existence of an arrangement.
		•		Delivery has occurred. Shipping documents and customer acceptance provisions, where applicable, are used to verify delivery.
		•		The fee is fixed or determinable. We assess whether the fee is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment.
		•		Collectibility is reasonably assured. We assess collectibility based primarily on creditworthiness of the customer or third party device manufacturer as determined by credit assessments and payment history.
	Substantially all of our customer arrangements include acceptance provisions that require testing of the network against specific performance criteria. We consider the following factors in our assessment of whether the acceptance provisions are substantive:
		•		whether the criteria are based on our standard performance criteria or are customer-specific;
		•		our experience with similar types of arrangements or products, as well as our experience with the specific customer;
		•		whether we would be successful in enforcing a claim for payment even in the absence of acceptance confirmation from the customer;
		•		the nature and complexity of the acceptance testing, including the planned duration of the acceptance period; and
		•		the significance of financial penalties, if any, associated with not meeting performance criteria.
	Considering our limited historical experience to date, we have concluded for our current arrangements that the acceptance provisions are substantive. When we consider acceptance provisions to be substantive, revenue is not recognized until we have determined acceptance is achieved. Once we have achieved acceptance, we recognize revenue as follows:
		•		Revenue from software that functions together with the tangible hardware elements to deliver the tangible products’ essential functionality is recognized upon delivery assuming all other revenue recognition criteria are met. Revenue from application software and related software elements which are not considered essential to the functionality of hardware devices is recognized ratably over the longest service period for post-contract customer support or PCS and professional services as we have not established VSOE for software or the related software elements.
		•		Revenue from our service offerings, including professional services such as network design and deployment support, managed services and SaaS, and ongoing customer support is recognized as services are delivered or on a proportional performance basis depending on the underlying pattern of performance.
		•		Revenue from hardware is recognized when title transfers.
	Amounts that are invoiced prior to a transaction meeting all of the above revenue recognition criteria, including customer acceptance criteria, are recorded in deferred revenue until such criteria are satisfied. For all periods presented herein, the amount and timing of revenue and product cost recognition has been, and for the near-term will be, dependent primarily on our ability to meet substantive customer acceptance criteria. We consider a variety of factors in estimating the timing of customer acceptance, which includes contractual milestones, project schedules, availability of resources, the nature and extent of remaining testing cycles, and other relevant information provided by our project management team. Accordingly, we expect that the timing of recognition of revenue and related product costs on both a quarterly and annual basis will not be easily predictable. In addition, it is possible that the amount of current deferred revenue and related deferred cost of revenue reflected as of a balance sheet date will be significantly higher or lower than the amount of deferred revenue and related deferred cost of revenue that is ultimately recognized as revenue and cost of revenue within the 12 months following the balance sheet date. We classify deferred revenue and deferred cost of revenue that we expect to recognize during the 12 months following the balance sheet date as current deferred revenue and current deferred cost of revenue on our balance sheet and the remainder as non-current deferred revenue and non-current deferred cost of revenue.
	Certain of our customer and third party device manufacturer contracts include contingency provisions, which impact our revenue recognition as such contingent amounts limit the amount of the total arrangement consideration under multiple deliverable contracts that can be allocated to delivered and accepted products and services. These provisions include penalties for late delivery, liquidated damages related to failure to meet milestones or deliver specified products or services, or credits to be issued upon the failure to meet service level arrangements. The amounts that could be paid under these provisions are typically limited and capped at amounts that do not exceed the maximum contract value. Accordingly, even in situations where we have received customer acceptance, we limit the revenue recognized for accepted products and services by the amount that could be paid under these provisions. We do not recognize these deferred amounts until the provisions have lapsed.
	In cases where we sell third-party products and services such as meters, hardware, services, software or software maintenance as part of the overall solution, we evaluate whether we act as principal or agent under the arrangement. The evaluation considers multiple factors, including whether we are the primary obligor under the arrangement with the utility customer, whether we bear the risk of loss and credit risk associated with the supply of third-party products and services, whether we have the ability to change the product or perform part of the service, and whether we have the ability to control the price charged to our customers for the third-party products and services. Revenue is presented on a gross basis when we conclude that we are the principal under the arrangement with respect to third-party products and services, and revenue is presented on a net basis when we conclude that we are acting as the agent. The majority of our revenue related to third-party products and services is recognized on a gross basis as we are generally acting as the principal under our arrangements.
	Shipping charges billed to customers were not significant for the years ended December 31, 2013, 2012, and 2011. Shipping charges are included in revenue, and the related shipping costs are included in cost of revenue in the accompanying consolidated statements of operations.
	Cost of Revenue
	Cost of product revenue includes contract manufacturing costs, including raw materials, components and associated freight, and normal yield loss. In addition, cost of product revenue includes compensation, benefits and stock-based compensation provided to our manufacturing personnel, overhead and other direct costs. Product costs are deferred upon shipment and are recognized in the period in which we recognize the related revenue. Period costs, which consist primarily of logistics costs, manufacturing ramp-up costs, expenses for inventory obsolescence, standard warranty costs and lower of cost or market adjustments are recognized in the period in which they are incurred.
	Costs of providing services include personnel-related costs, depreciation and amortization, and software hosting costs. Costs of providing services are not deferred and are included in cost of revenue in the period in which they are incurred. Accordingly, there are no deferred service costs of revenue in the accompanying balance sheets.
	Deferred Revenue and Deferred Cost of Revenue
	Deferred revenue results from transactions where we have billed the customer for product shipped or services performed but all revenue recognition criteria have not yet been met.
	Deferred cost of revenue is recorded for products for which ownership (typically title and risk of loss) has transferred to the customer, but for which criteria for revenue recognition have not been met. We only defer tangible direct costs associated with hardware products delivered. Cost of revenue for providing services is not deferred, but is expensed in the period incurred. Deferred cost of revenue associated with deferred product revenue is recorded at the standard inventory cost at the time of shipment. We evaluate deferred cost of revenue for recoverability based on multiple factors, including whether net revenues less related direct costs will exceed the amount of deferred cost of revenue based on the terms of the overall arrangement. To the extent that deferred cost of revenue is determined to be unrecoverable, we adjust deferred cost of revenue with a charge to product cost of revenue in the current period. In connection with our recoverability assessments, we have not incurred significant impairment charges through December 31, 2013.
	We recognize deferred revenue and associated deferred cost of revenue once all revenue recognition criteria have been met.
	Product Warranty
	We provide warranties for substantially all of our products. Our standard warranty period extends from one to five years. We accrue for costs of standard warranty at the time of product shipment, and record changes in estimates to warranty accruals when it is probable a liability has been incurred and the amount of loss can be reasonably estimated.
	At the time of product shipment, we estimate and accrue for the amount of standard warranty cost and record the amount as a cost of revenue. Determining the amount of warranty costs requires management to make estimates and judgments based on historical claims experience, industry benchmarks, test data and various other assumptions including estimated field failure rates that are believed to be reasonable under the circumstances. The amount of warranty costs accrued are net of warranty obligations to be fulfilled by our suppliers. The results of these judgments formed the basis for our estimate of the total charge to cover anticipated customer warranty, repair, return and replacement and other associated costs. Should actual product failure rates, claim levels, material usage or supplier warranties on parts used in our products differ from our original estimates, revisions to the estimated warranty liability could result in adjustments to our cost of revenue in future periods.
	Certain of our standard product warranty obligations require us to reimburse a customer for installation and other related costs in the event that field reliability rates fall below contractually specified thresholds. We consider the probability that we will have to pay such incremental warranty costs based on the expected performance of a delivered product when we record new warranty obligations issued in a period as well as when we determine if any changes are required to our original estimates for pre-existing warranty obligations.
	Our warranty obligations are affected by product failure rates, claims levels, material usage and supplier warranties on parts included in our products. Because our products are relatively new and we do not have the benefit of long-term experience observing products’ performance in the field, it is possible that the estimates of a product’s lifespan and incidence of claims could vary from period to period.
	In certain customer arrangements, we have provided extended warranties for periods of up to 15 years following the initial standard warranty period. We recognize revenue associated with extended warranties over the extended warranty period when the extended warranty period commences. Costs associated with providing extended warranties are expensed as incurred during the extended warranty period.
Supplier Concentrations and Other Inventory Risks
We have arrangements under which substantially all of our manufacturing activity is subcontracted to third-party vendors. Currently our sole manufacturing relationship is with Plexus Corp., who provides us with a wide range of operational and manufacturing services, including material procurement, final assembly, test quality control, warranty repair, and shipment to our customers and third-party vendors. Contract manufacturing activities are conducted in the United States and are undertaken based on management’s product demand forecasts. Our contract manufacturer procures components necessary to assemble the products anticipated by management’s forecast and test the products according to our quality specifications. If the components are unused for specified periods of time, we may incur carrying charges or obsolete material charges for components that our contract manufacturers purchased to build products to meet our product demand forecasts. Our communications modules and other hardware products consist of commodity parts and certain custom components. Our components are generally available from multiple sources or suppliers. However, some components used in our products are purchased from single or limited sources.
Finished goods are reported as inventory until title transfers to the customer. Consigned finished goods inventory that is maintained at customer locations is also reported as inventory until consumption or acceptance of the product by the customer. We account for consigned inventory on a first-in, first-out basis and record lower of cost or market or obsolete material charges when appropriate.
Concentration of Credit and Customer Risks
Our sales are currently concentrated with a small group of customers and third party device manufacturers principally located in the United States and Australia. In evaluating customer concentration risk, we attribute revenue to our customers, including amounts billed to third party device manufacturers for our communications modules.
The following table summarizes the percentage of revenue related to our customers’ deployments in excess of 10% of total revenue:
		Year Ended December 31,
		2013			2012			2011
PG&E			39	%		30	%		34	%
FPL			20			31			26
OG&E			—			18			—
SMUD			—			—			12
Each of these total revenue percentages includes amounts related to the customers’ deployments that were billed directly to our third party device manufacturers, as well as direct revenue from the customers. We typically extend credit to our customers and third party device manufacturers and do not require collateral or other security in support of accounts receivable. We attempt to mitigate the credit risk in our trade receivables through our credit evaluation process and payment terms. We analyze the need to reserve for potential credit losses and record allowances for doubtful accounts when necessary. To date, we have not had any significant write-offs of uncollectible accounts receivable, and there was no allowance for doubtful accounts as of December 31, 2013 and 2012.
The following table summarizes the percentage of accounts receivable from customers and third party device manufacturers in excess of 10% of accounts receivable:
		December 31,
		2013			2012
Baltimore Gas and Electric Company			26	%		26	%
Landis + Gyr AG (acquired by Toshiba Corporation)			11			—
Commonwealth Edison Company			10			—
Virginia Electric and Power Company			10			—
Secure Meters			—			16
Progress Energy			—			15
General Electric Company			—			10
Advertising Costs
We expense advertising costs as incurred. Advertising costs were $2.2 million, $2.5 million, and $2.5 million for each of the years ended December 31, 2013, 2012, and 2011.
Property and Equipment, Net
Property and equipment are stated at cost. Depreciation is calculated using the straight-line method over the following estimated useful lives:
Software		3 to 7 years
Computer and network equipment		2 to 5 years
Machinery and equipment		3 to 5 years
Furniture and fixtures		5 to 7 years
Leasehold improvements		Lesser of the lease term or the estimated useful lives of the improvements, generally 1 to 4 years
Long-Lived Assets
We evaluate long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. For the years ended December 31, 2013, 2012, and 2011, no impairment losses were recorded.
Research and Development
Research and development costs are expensed as incurred. Under our current practice of developing new products, technological feasibility of the underlying software is not established until substantially all product development and testing is complete, which generally includes the development of a working model. Our products are released within a short period of time after achieving technological feasibility.
Deferred Issuance Costs
Costs directly associated with the planned issuance of equity or debt instruments are capitalized and recorded as deferred issuance costs until the issuance of such instruments. Costs directly associated with debt instruments are capitalized as deferred issuance costs and amortized over the contractual term of the debt instrument utilizing the effective interest method. Deferred issuance costs included in other long-term assets were $5.0 million as of December 31, 2012. In connection with our IPO, deferred issuance costs previously recorded in other long-term assets were recorded as an off-set to the equity proceeds. As of December 31, 2013, there were no deferred issuance costs.
Corporate Bonus Incentive Plan
Our corporate bonus incentive plan is funded by a combination of cash and restricted stock units, at management’s discretion. The restricted stock units granted prior to our IPO contained a performance-based condition and vested upon the effectiveness of the Registration Statement on Form S-1. As a result, we recorded the related stock-based compensation for these awards in the year ended December 31, 2013 (as discussed above—Initial Public Offering). Subsequent to our IPO, we accrue and record the related stock-based compensation for corporate bonus amounts payable under this plan in connection with the period in which it is earned.
Stock-Based Compensation
We measure and recognize compensation expense for all stock-based awards made to employees and directors, including stock options, restricted stock, restricted stock units, and employee stock purchase plan, based on estimated fair values. The fair values of stock options and our 2013 Employee Stock Purchase Plan (please refer to Note 9 Stock Based Compensation for further discussion) are estimated at the date of grant using the Black-Scholes-Merton option pricing model, which includes assumptions for the dividend yield, expected volatility, risk-free interest rate, and expected life. The fair values of restricted stock and restricted stock units are determined based upon the fair value of the underlying common stock at the date of grant. We expense stock-based compensation, adjusted for estimated forfeitures, using the straight-line method over the vesting term of the award. Our excess tax benefits cannot be credited to stockholders’ equity until the deduction reduces cash taxes payable; accordingly, we realized no excess tax benefits during any of the periods presented in the accompanying financial statements. The amount of capitalized stock-based employee compensation cost as of December 31, 2013 and 2012 was not material.
Preferred Stock Warrant Liability
We accounted for freestanding warrants to purchase shares of our convertible preferred stock as a liability on the consolidated balance sheets. The convertible preferred stock warrants were recorded as a liability because the underlying shares of convertible preferred stock were contingently redeemable and, therefore, could have obligated us to transfer assets at some point in the future (see Note 7 Convertible Preferred Stock and Preferred Stock Warrants). The warrants were recorded at fair value upon issuance and were subject to remeasurement to fair value at each balance sheet date, with any change in fair value recognized as a component of other income (expense), net, on the consolidated statements of operations. In connection with our IPO, we reduced our preferred stock warrant liability by $11.2 million and recorded a loss of $0.8 million in the year ended December 31, 2013 resulting from our payment of $12.0 million as consideration for the termination of certain warrants to purchase shares of Series A preferred stock and all warrants to purchase shares of Series C preferred stock, which occurred immediately prior to the effectiveness of our IPO. We reclassified the preferred stock warrant liability for the surviving warrant to purchase shares of Series A preferred stock and all warrants to purchase shares of Series E preferred stock to additional paid-in capital, as these warrants converted to warrants to purchase shares of common stock. As of December 31, 2013, there were no longer any preferred stock warrants outstanding.
Income Taxes
Income taxes are calculated using the asset and liability method. Deferred income taxes are recorded for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. We record a valuation allowance to reduce our deferred tax assets to the amount of future tax benefit that we believe is more likely than not to be realized.
We follow a two-step approach to recognizing and measuring tax benefits associated with uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if, based on the technical merits, it is more likely than not that the tax position will be sustained upon examination by a taxing authority, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement with a taxing authority. We recognize any interest and penalties related to uncertain tax positions in the provision for income taxes line of our consolidated statements of operations.
Recent Accounting Pronouncements
In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740)-Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The standard requires us to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss (NOL) carryforward or other tax credit carryforward when settlement in this manner is available under applicable tax law. We early adopted this guidance during the year ended December 31, 2013. The adoption of this guidance did not have a material impact on our consolidated financial statements.
In February 2013, the FASB issued Accounting Standards Update No. 2013-02, Comprehensive Income (Topic 220)-Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. The standard requires entities to present (either on the face of the income statement or in the notes) the effects on the line items of the income statement for amounts reclassified out of accumulated other comprehensive income. We adopted this guidance on January 1, 2013, and the adoption did not have an impact on our consolidated financial statements.

Net_Loss_Per_Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Net Loss Per Share	'
	2. NET LOSS PER SHARE
	In connection with our IPO, all of our outstanding convertible preferred stock converted into common stock. In addition, we recognized a deemed dividend of $105.0 million to common stockholders on the date of conversion, as discussed further in Note 7 Convertible Preferred Stock and Preferred Stock Warrants. Basic net loss per share applicable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share applicable to common stockholders is computed by giving effect to all potential shares of common stock, including convertible debt, stock options, warrants and convertible preferred stock, to the extent dilutive. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential common shares outstanding would have been anti-dilutive.
	The following table sets forth the computation of historical basic and diluted net loss per share (in thousands, except per share data):
		Year Ended December 31,
		2013			2012			2011
	Net loss	$	(66,807	)	$	(89,717	)	$	(92,359	)
	Deemed dividend to convertible preferred shareholders		(105,000	)		—			—
	Net loss attributable to common stockholders	$	(171,807	)	$	(89,717	)	$	(92,359	)
	Weighted-average shares used to compute net loss per share, basic and diluted		37,877			3,670			3,543
	Basic and diluted net loss per share attributable to common stockholders	$	(4.54	)	$	(24.45	)	$	(26.07	)
	The following potential common shares outstanding were excluded from the computation of diluted net loss per share because including them would have been anti-dilutive (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Employee equity incentive plans		7,760			4,847			5,547
	Warrants to purchase convertible preferred stock		—			386			386
	Warrants to purchase common stock		—			50			50
	Convertible preferred stock		—			22,366			22,366
	Total common stock equivalents		7,760			27,649			28,349
	Also excluded from the computation of diluted net loss per share was the impact of issuing shares for the potential conversion of the subordinated convertible notes described in Note 5 Borrowings, which converted in connection with our IPO.

Financial_Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Financial Instruments	'
	3. FINANCIAL INSTRUMENTS
	Cash, Cash Equivalents, and Short-term Investments
	Cash, cash equivalents, and short-term investments consisted of the following as of December 31, 2013 (in thousands):
		Amortized			Unrealized			Unrealized			Estimated
		Cost			Gains			Losses			Fair Value
	Current assets:
	Cash	$	52,346		$	—		$	—		$	52,346
	Cash equivalents:
	Money market mutual funds		30,250			—			—			30,250
	Total cash equivalents		30,250			—			—			30,250
	Short-term fixed income securities:
	U.S. government and agency obligations		41,991			84			(21	)		42,054
	U.S. and foreign corporate debt securities		18,366			76			(1	)		18,441
	Foreign governments and multi-national agency obligations		2,764			—			(3	)		2,761
	Total short-term investments		63,121			160			(25	)		63,256
	Total cash, cash equivalents and short-term investments	$	145,717		$	160		$	(25	)	$	145,852
	We held no cash equivalents or short-term investments as of December 31, 2012.
	As of December 31, 2013, approximately 41%, 34%, and 21% of our cash, cash equivalents, and short-term investments were held with three financial institutions. As of December 31, 2012, approximately 50% and 44% of our cash were held with two financial institutions.
	Contractual Maturities
	The contractual maturities of cash equivalents and short-term investments held at December 31, 2013 consisted of the following (in thousands):
		Amortized			Aggregate
		Cost Basis			Fair Value
	Due within one year	$	44,477		$	44,474
	Due after 1 year through 3 years		48,894			49,032
	Total cash equivalents & short-term investments	$	93,371		$	93,506
	The following table presents gross unrealized losses and fair values for those investments that were in an unrealized loss position as of December 31, 2013, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in thousands):
		As of December 31, 2013
		Total (Less Than 12 Months)
		Fair Value			Unrealized Loss
	U.S. and foreign corporate debt securities	$	4,247		$	(1	)
	Foreign governments and multi-national agency obligations		2,761			(3	)
	U.S. government and agency obligations		12,566			(21	)
	Total	$	19,574		$	(25	)
	We periodically review our marketable debt securities for other-than-temporary impairment. We consider factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. We also consider whether it is more likely than not that we will be required to (i) sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During the year ended December 31, 2013, we did not recognize any other-than-temporary impairment loss.
	Fair Value Measurements
	We measure certain financial assets and liabilities at fair value on a recurring basis.
	The measurements of fair value were established based on a fair value hierarchy that prioritizes the inputs. This hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The fair value framework requires the categorization of assets and liabilities into three levels based upon the assumptions (inputs) used to price the assets or liabilities. The guidance for fair value measurements requires that assets and liabilities carried at fair value be classified and disclosed in one of the following categories:
	Level 1—Quoted (unadjusted) prices in active markets for identical assets or liabilities.
	Level 2—Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability.
	Level 3—Unobservable inputs in which there is little or no market data, which requires us to develop our own assumptions. Our Level 3 liabilities consist of warrants to purchase convertible preferred stock and embedded derivatives related to our convertible promissory notes.
	Level 1 measurements are obtained from real-time quotes for transactions in active exchange markets involving identical assets. Level 2 measurements are obtained from readily available pricing sources for comparable instruments, identical instruments in less active markets, or models using market observable inputs. We did not have any transfers of financial instruments between valuation levels during the year ended December 31, 2013.
	As of December 31, 2013, financial assets recorded at fair value on a recurring basis were determined using the following inputs (in thousands):
		Fair Value Measurement Using
		Quoted Prices in			Significant Other			Significant			Total
		Active Markets			Observable			Unobservable
		for Identical			Inputs			Inputs
		Instruments			(Level 2)			(Level 3)
		(Level 1)
	Cash equivalents:
	Money-market funds	$	30,250		$	—		$	—		$	30,250
	Total cash equivalents		30,250			—			—			30,250
	Short-term investments:
	U.S. Government and agency obligations		—			42,054			—			42,054
	U.S. and foreign corporate debt securities		—			18,441			—			18,441
	Foreign governments and multi-national agency obligations		—			2,761			—			2,761
	Total short-term investments		—			63,256			—			63,256
	Total assets measured at fair value	$	30,250		$	63,256		$	—		$	93,506
	As of December 31, 2013, there were no financial liabilities recorded at fair value on a recurring basis.
	As of December 31, 2012, there were no financial assets recorded at fair value on a recurring basis.
	As of December 31, 2012, financial liabilities recorded at fair value on a recurring basis were determined using the following inputs (in thousands):
		Fair Value Measurement Using
		Quoted Prices in			Significant Other			Significant			Total
		Active Markets			Observable			Unobservable
for Identical		Inputs			Inputs
Instruments		(Level 2)			(Level 3)
(Level 1)
Liabilities:
Preferred stock warrants	$	—		$	—		$	11,261		$	11,261
Embedded derivative		—			—			3,519			3,519
Total liabilities measured at fair value	$	—		$	—		$	14,780		$	14,780
Convertible Promissory Notes and Compound Embedded Derivatives
As of December 31, 2012, we had outstanding a $24.0 million convertible note, or the December 2011 Note and a $30.0 million convertible note, or the February 2012 Note, each of which contained certain features that were accounted for as compound bifurcated derivative instruments. The compound bifurcated derivative instruments were recorded on the balance sheet at fair value at issuance and at each balance sheet date as discussed further in Note 5 (Borrowings).
At issuance on December 6, 2011, we estimated the fair value of the December 2011 Note, including the compound embedded derivative, at $24.0 million, which approximated the original transaction value with an unrelated third party, and which approximated the fair value at December 31, 2011. At issuance on February 21, 2012, we estimated the fair value of the February 2012 Note, including the compound embedded derivative, at $30.0 million, which approximated the original transaction value with an unrelated third party. At issuance of the December 2011 Note and February 2012 Note, we determined that the fair values of the respective compound embedded derivatives were $1.5 million and $3.6 million, by utilizing a Monte Carlo simulation model using Level 3 inputs. The Monte Carlo simulation model measured the fair value of the compound embedded derivative utilizing a probability weighted discounted cash flow model in a risk-neutral framework for probability of the occurrence of certain of the conversion features as discussed in Note 5 (Borrowings). As of December 31, 2012, the fair values of the compound embedded derivatives related to the December 2011 Note and February 2012 Note were $1.8 million and $1.7 million, respectively.
The compound embedded derivatives were marked to market each period and the changes in the fair value were included as a non-cash item in other income (expense), net on our consolidated statements of operations. In connection with our IPO, the December 2011 Note and February 2012 Note, together with accrued interest, were converted into shares of common stock and accounted for as debt extinguishment, as discussed further in Note 5 (Borrowings).
As of December 31, 2012, the carrying amount and estimated fair value of the convertible promissory notes and compound embedded derivatives using Level 3 measurements were as follows (in thousands):
	Carrying			Estimated
	Amount			Fair Value
Convertible promissory notes	$	52,800		$	54,846
Compound embedded derivatives		3,519			3,519
Fair Value Remeasurement of Preferred Stock Warrants
We recorded the warrants as liabilities at their initial grant date fair value and thereafter recorded gains and losses arising from the change in fair value as a component of other income, net, in the consolidated statements of operations. We recorded unrealized gains of $2.3 million and $3.5 million for the years ended December 31, 2012 and 2011, respectively. As of December 31, 2013, there were no longer any preferred stock warrants outstanding, as discussed further in Note 7 (Convertible Preferred Stock and Preferred Stock Warrants).
The fair value of the warrant liability was estimated using a probability weighted expected return model, which determines the present value of future distributions that equity classes may realize based on the probability of occurrence of certain sale or IPO exit events.
The following table provides a roll-forward of the fair value of the convertible preferred stock warrants and compound embedded derivatives valued with Level 3 inputs (in thousands):
	Year Ended December 31,
	2013			2012			2011
Beginning of period	$	14,780		$	15,018		$	17,035
Issuance of convertible preferred stock warrants		—			—			9
Remeasurement and termination of convertible preferred stock warrants		(11,261	)		(2,267	)		(3,516	)
Issuance of compound embedded derivatives		—			3,640			1,490
Remeasurement and extinguishment of compound embedded derivatives		(3,519	)		(1,611	)		—
End of period	$	—		$	14,780		$	15,018

Balance_Sheet_Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'
Balance Sheet Details	'
	4. BALANCE SHEET DETAILS
	Deferred Revenue and Deferred Cost of Revenue
	The following table details the activity in deferred revenue (in thousands):
		Year Ended December 31,
		2013			2012
	Deferred revenue, beginning of period	$	508,056		$	400,460
	Revenue deferred in the period		343,455			304,333
	Revenue recognized in the period		(326,858	)		(196,737	)
	Deferred revenue, end of period	$	524,653		$	508,056
	The following table details the activity in deferred cost of revenue (in thousands):
		Year Ended December 31,
		2013			2012
	Deferred cost of revenue, beginning of period	$	245,163		$	206,303
	Costs deferred related to revenue deferred in the period		170,213			147,229
	Cost of revenue recognized in the period		(139,253	)		(108,369	)
	Deferred cost of revenue, end of period	$	276,123		$	245,163
	Inventory
	Inventory consisted of the following (in thousands):
		December 31,
		2013			2012
	Component parts	$	141		$	299
	Finished goods		4,209			7,432
	Inventory	$	4,350		$	7,731
	Finished goods inventory included consigned inventory totaling $2.8 million and $3.5 million as of December 31, 2013 and 2012, respectively.
	Property and Equipment, Net
	Property and equipment, net, consisted of the following (in thousands):
		December 31,
		2013			2012
	Computer and network equipment	$	15,328		$	13,356
	Software		13,003			10,970
	Machinery and equipment		8,543			7,807
	Furniture and fixtures		929			713
	Leasehold improvements		1,161			1,033
	Total property and equipment		38,964			33,879
	Less: Accumulated depreciation and amortization		(26,600	)		(21,178	)
	Property and equipment, net	$	12,364		$	12,701
	Depreciation and amortization expense associated with property and equipment, including amounts for assets held under capital leases, was $6.5 million, $7.1 million, and $6.7 million for the years ended December 31, 2013, 2012, and 2011, respectively.
	Machinery and equipment included $6.3 million and $5.3 million of assets held under capital leases at December 31, 2013 and 2012, respectively, with corresponding accumulated amortization of $3.8 million and $2.2 million, respectively.
	Software included $3.5 million and $3.0 million of assets held under capital leases at December 31, 2013 and 2012, respectively, with corresponding accumulated amortization of $2.2 and $1.6 million, respectively.
	Other Long-Term Assets
	Other long-term assets consisted of the following (in thousands):
		December 31,
		2013			2012
	Goodwill and acquired intangible assets, net	$	671		$	864
	Prepaid expenses and deposits, non-current		896			10,390
	Other long-term assets	$	1,567		$	11,254
	Acquired intangibles include developed technology and customer relationships. The gross carrying amount of developed technology was $962,000 as of December 31, 2013 and 2012. Accumulated amortization as of December 31, 2013 and 2012 was $738,000 and $545,000, respectively. The gross carrying amount of customer relationships was $260,000 as of December 31, 2013 and 2012. Accumulated amortization as of December 31, 2013 and 2012 was $260,000.
	We have recorded amortization expense for the years ended December 31, 2013, 2012, and 2011 of $192,000, $192,000, and $289,000, respectively. We expect to incur amortization expense of $192,000 and $33,000 in 2014 and 2015, respectively.
	The carrying amount of goodwill was $447,000 as of December 31, 2013 and 2012, which reflects the original acquisition value.
	Accrued Liabilities
	Accrued liabilities consisted of the following (in thousands):
		December 31,
		2013			2012
	Accrued payroll and related expenses	$	10,677		$	5,131
	Accrued operating expenses		3,949			3,488
	Product warranty, current		2,985			3,109
	Sales, property and income taxes		1,202			594
	Other		2,469			2,509
	Accrued liabilities	$	21,282		$	14,831
	Accumulated Other Comprehensive Income (AOCI)
	The components of AOCI, net of tax, were as follows (in thousands):
		Foreign Currency			Unrealized Gains			Total
		Translation			on Available for
Adjustments		Sale Securities
Balance as of December 31, 2012	$	(136	)	$	—		$	(136	)
Other comprehensive income (loss) before reclassification		182			84			266
Amounts reclassified from AOCI		—			—			—
Other comprehensive income		182			84			266
Balance as of December 31, 2013	$	46		$	84		$	130

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Borrowings	'
	5. BORROWINGS
	Credit Facility
	We have available a line of credit with a bank, which originally provided for advances and the issuance of letters of credit of up to $40 million. On May 8, 2013, we amended our credit agreement to increase the available capacity from $40 million to $50 million. As of December 31, 2013, there were no borrowings outstanding under the credit agreement; however, $9.8 million of letters of credit were outstanding, leaving $40.2 million of available capacity for cash borrowings or additional letters of credit, subject to compliance with financial covenants and other customary conditions to borrowings. As of December 31, 2013 we were in compliance with the financial covenants in the credit agreement.
	The credit agreement is guaranteed by certain of our accounts receivable, inventory and cash. Loans under the credit agreement bear interest at the bank’s prime rate plus a margin. The credit agreement will terminate and all amounts owing thereunder will be due and payable on May 17, 2015, unless (a) the commitments are terminated earlier, either at our request or, if an event of default occurs, by the bank (or automatically in the case of certain bankruptcy-related events of default), or (b) the maturity date is extended upon our request, subject to the agreement of the bank. The credit agreement contains customary representations, warranties, affirmative and negative covenants, including financial covenants, events of default and indemnification provisions in favor of the bank. The negative covenants include restrictions regarding the incurrence of liens, subject to certain exceptions. The financial covenants require us to meet monthly financial tests with respect to liquidity ratio and unrestricted cash.
	Subordinated Convertible Notes
	In December 2011, we issued the December 2011 Note for an aggregate principal amount of $24.0 million, with a maturity date of December 6, 2014. Interest accrued for the first six months at a rate of 3.0% per year and increased by 1.0% every six months to a maximum of 6.0% per year.
	The unpaid principal amount of the December 2011 Note, together with any interest accrued but unpaid thereon, were convertible (a) automatically into shares of a new series of convertible preferred stock at a price per share equal to 85% of the per share selling price of the new preferred stock upon completion of a financing, (b) automatically into shares of common stock immediately prior to the closing of an initial public offering of our common stock at a conversion price equal to 88% of the price to the public in such offering, or (c) at any time upon the election of the investor into shares of Series E preferred stock at a conversion price equal to $50.00 per share. If the December 2011 Note had not automatically converted immediately prior to the closing of our IPO, the outstanding amount of the December 2011 Note would have been due prior to a change of control. We also could have elected to repay the outstanding balance prior to maturity subject to a 7% prepayment penalty with 10 days’ written notice.
	In February 2012, we issued the February 2012 Note for an aggregate principal amount of $30.0 million, with a maturity date of February 21, 2015. Interest accrued for the first six months at a rate of 3.0% per year and increased by 1.0% every six months to a maximum of 6.0% per year.
	The unpaid principal amount of the February 2012 Note, together with any interest accrued but unpaid thereon, were convertible (a) upon the election of the investor into shares of a new series of convertible preferred stock at a price per share equal to 88% of the per share selling price of the new preferred stock upon completion of a financing, or (b) automatically into shares of common stock immediately prior to the closing of an initial public offering of our common stock at a conversion price equal to 88% of the price to the public in such offering. If the February 2012 Note had not automatically converted immediately prior to the closing of our IPO, the outstanding amount of the February 2012 Note would have been due prior to a change of control. We also could have elected to repay the outstanding balance prior to maturity subject to a 7% prepayment penalty with 10 days’ written notice.
	We concluded that the conversion and repayment features of both the December 2011 Note and the February 2012 Note were accounted for as embedded derivative instruments, and accordingly were bundled as a compound embedded derivative pursuant to the guidance of ASC 815, Derivatives and Hedging. These features were not considered clearly and closely related to either the December 2011 Note or the February 2012 Note and did not qualify for any exceptions from derivative accounting. Therefore, they were bifurcated as a compound embedded derivative that were recorded on the balance sheet at fair value at issuance and at each balance sheet date the notes remained outstanding.
	We concluded that the fair values of the December 2011 Note and February 2012 Note, including the compound embedded derivative, were $24.0 million and $30.0 million, respectively, which approximated the original transaction value with an unrelated third party. The fair values of the compound embedded derivative at the date of issuance for the December 2011 Note and the February 2012 Note were $1.5 million and $3.6 million, respectively, which created an issuance discount for each convertible note that was amortized over the term using the effective interest rate method. We determined the fair value of each compound embedded derivative using a Monte Carlo simulation model which measured the probability weighted discounted cash flows in a risk-neutral framework for the occurrence of each of the conversion features in which the outstanding amount of the convertible note would be converted into shares of our stock or would be repaid to the lenders in cash.
	In connection with our IPO, the December 2011 Note and February 2012 Note together with contractual accrued interest of $2.3 million thereon through March 18, 2013, the closing date of our IPO, converted into 3,764,954 shares of common stock based on the outstanding principal and accrued interest at a conversion price equal to 88% of the IPO price of $17.00 per share. The conversion of the convertible notes and issuance of common stock were accounted for as debt extinguishments and accordingly, the convertible notes, unamortized debt issuance costs and bifurcated compound embedded derivatives were removed at their respective carrying amounts and the shares of common stock issued were measured at fair value based on the closing price on the date our IPO closed. As a result, we recorded a loss on debt extinguishments of $22.9 million in the year ended December 31, 2013.
	The following table provides a roll-forward of the carrying value of the convertible notes and compound embedded derivatives (in thousands):
		Convertible			Compound			Total
		Promissory			Embedded
		Notes			Derivatives
	Balances at December 31, 2012	$	52,800		$	3,519		$	56,319
	Accrued interest on convertible promissory notes		558			—			558
	Accretion of discount on convertible promissory notes		377			—			377
	Conversion of convertible promissory notes and embedded derivatives		(53,735	)		(3,519	)		(57,254	)
	Balances at December 31, 2013	$	—		$	—		$	—
	We had classified the compound embedded derivatives as a long-term liability and presented them together with the carrying value of the convertible notes on our consolidated balance sheet as of December 31, 2012. The effective interest rate for the December 2011 Note and February 2012 Note were 6.89% and 10.16%, respectively. The outstanding amount including principal and accrued interest based on the contractual interest rate was $55.8 million as of December 31, 2012.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	6. COMMITMENTS AND CONTINGENCIES
	Product Warranty
	Product warranty obligation is presented as follows on the consolidated balance sheets (in thousands):
		December 31,
		2013				2012
	Warranty obligation—classified in accrued liabilities	$	2,985			$	3,109
	Warranty obligation—classified in other liabilities		3,104				3,207
		$	6,089			$	6,316
	Product warranty activity was as follows (in thousands):
		Year Ended
		December 31,
		2013				2012
	Warranty obligation—beginning of period	$	6,316			$	9,631
	Warranty expense for new warranties issued		1,406				1,372
	Utilization of warranty obligation		(1,767	)			(2,671	)
	Changes in estimates for pre-existing warranties		134				(2,016	)
	Warranty obligation—end of period	$	6,089			$	6,316
	During the years ended December 31, 2013 and 2012, we revised our estimated warranty liability to reflect updated product field reliability experience and recorded an increase (reduction) of product warranty liability and product cost of revenue by $0.1 million and ($2.0) million, respectively.
	As of December 31, 2013 and 2012, we had deferred revenue associated with extended warranty arrangements of $206,000 and $362,000, respectively, included in other current liabilities, and $7.1 million and $5.5 million, respectively, included in other long-term liabilities on our consolidated balance sheets.
	Operating and Capital Leases
	Our primary operating lease commitment at December 31, 2013, related to our headquarters in Redwood City, California, requires monthly lease payments through December 2016. We recognize rent expense on a straight-line basis over the lease period. Where leases contain escalation clauses, rent abatements, or concessions, such as rent holidays and landlord or tenant incentives or allowances, we apply them in the determination of straight-line rent expense over the lease term. Rent expense for all facility leases was $4.9 million, $4.0 million, and $3.5 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	In March 2012 and June 2012, we sold assets to a financial institution. Concurrently with the sales, we entered into separate agreements to lease the property back from the financial institution over a minimum lease term of three years. The subsequent leasebacks qualified as normal leasebacks and are classified as capital leases. The gains and losses on the transactions were not material.
	The following table provides a summary of the sale leaseback transactions that were outstanding as of December 31, 2013 (dollars in thousands):
	Lease Commencement	Lease Termination		Term				Interest		Financed
				(months)				rate		Amount
	Mar-12	March 2015			36				7.4		716
	Jun-12	Jun-15			36				6.7		960
										$	1,676
	As of December 31, 2013, the future minimum commitments under our operating and capital leases were as follows (in thousands):
		Operating				Capital
		Leases				Leases
	2014	$	5,088			$	1,752
	2015		5,145				1,162
	2016		3,928				112
	2017		179				—
	2018		183				—
	2019 and thereafter		1,075				—
	Net minimum lease payments	$	15,598				3,026
	Less amount representing interest						(188	)
	Present value of net minimum capital lease payments					$	2,838
	Legal Contingencies
	We were named in a lawsuit filed in September 2010 in the Superior Court of the State of California, San Mateo County (Edwards v. Silver Spring Networks). The lawsuit claims to be a “class action” on behalf of California consumers, and alleges that smart meters are defective and generate incorrect bills. We have filed a motion to dismiss this case and, in September 2011, the San Mateo Superior Court granted our motion without leave to amend as to two of the plaintiffs’ causes of action and with leave to amend as to a third claim. In February 2012, the plaintiffs filed an amended complaint, to which we filed an answer denying the plaintiffs’ allegations in May 2012. In August 2012, the plaintiffs filed a second amended complaint, and in September 2012, we filed a demurrer to one of the two claims asserted in the second amended complaint, which was overruled by the court. In November 2012, the plaintiffs filed a motion for class certification, for which a hearing was held in January 2013. In April 2013, the court denied the class certification motion without prejudice, but allowed the plaintiffs to file a revised class certification motion, which the plaintiffs filed in June 2013. A hearing on the revised class certification motion was held in September 2013, and the court denied the revised class certification motion in December 2013. We intend to continue vigorously defending against the action.
	In June 2011, EON Corp. IP Holdings, LLC, a non-producing entity, or EON, filed suit in United States District Court for the Eastern District of Texas, Tyler Division against us and a number of smart grid providers. Other defendants include Landis+Gyr AG (acquired by Toshiba Corporation), Aclara Power-Line Systems Inc., Elster Solutions, LLC, Itron, Inc. and Trilliant Networks Inc. This lawsuit alleges infringement of United States Patent Nos. 5,388,101, 5,481,546, and 5,592,491 by certain networking technology and services that we and the other defendants provide. We filed amended answers, affirmative defenses and counterclaims in August 2012, September 2012, October 2012 and November 2012 denying the plaintiff’s allegations and that plaintiff’s patents are invalid. The trial has been scheduled for April 2014. All of the other named defendants in the case have settled with EON. We believe that we have meritorious defenses to EON’s allegations and intend to continue vigorously defending against the action.
	In September 2011 TransData, Inc., or TransData, filed suit in United States District Court for the Western District of Oklahoma, against our customer, Oklahoma Gas & Electric Company, alleging infringement of United States Patent Nos. 6,181,294, 6,462,713, and 6,903,699 by certain wireless communication-enabled meters. Together with the meter manufacturer, General Electric Company, we have agreed to indemnify and defend Oklahoma Gas & Electric Company in connection with the TransData suit. An early claim construction hearing was held regarding one claim term in February 2013, which the court ruled upon in June 2013. A hearing for the full claim construction was held in September 2013, on which the court issued an order in October 2013. We believe that we have meritorious defenses to TransData’s allegations, and together with General Electric Company intend to vigorously defend against the action.
	In March 2013, Linex Technologies, Inc., a non-producing entity, or Linex, filed suit against us in United States District Court for the Southern District of Florida. The complaint alleges that certain of our networking technology infringes United States Patent Nos. 6,493,377 and 7,167,503. We filed an answer in May 2013. In January 2014, the court granted the plaintiff’s request for a stay of the matter, pending reexamination of the patents at issue by the U.S. Patent and Trademark Office. We believe that we have meritorious defenses to Linex’s allegations and intend to continue vigorously defending against the action.
	As of December 31, 2013, the Company has recorded an immaterial charge related to certain legal proceedings described above. Other than for the matters that the Company has recognized in the consolidated financial statements, it has not recorded any amounts for contingent losses associated with the matters described above based on its belief that losses, while reasonably possible, are not probable. Unless otherwise stated, the Company is currently unable to predict the final outcome of these lawsuits and therefore cannot determine the likelihood of loss nor estimate a range of possible loss.
	We are directly involved with various unresolved legal actions and claims, and indirectly are involved with proceedings by administrative bodies such as public utility commissions, arising in the ordinary course of business. We do not believe that any liability from any reasonably foreseeable disposition of such legal actions and claims, individually or in the aggregate, would have a material effect on our consolidated financial statements. There are many uncertainties associated with any litigation or claim, and we cannot be certain that these actions or other third-party claims will be resolved without costly litigation, fines and/or substantial settlement payments. If that occurs, our business, financial condition and results of operations could be materially and adversely affected. If information becomes available that causes us to determine that a loss in any of our pending litigation matters, claims or settlements is probable, and a reasonable estimate of the loss associated with such events can be made, we will record the estimated loss at that time.
	Customer Performance and Other Commitments
	Certain customer agreements require us to obtain letters of credit or surety bonds in support of our obligations under such arrangements. These letters of credit or surety bonds typically provide a guarantee to the customer for future performance, which usually covers the deployment phase of a contract and may on occasion cover the operations and maintenance phase of service contracts.
	As of December 31, 2013 and 2012, we had a total of $9.8 million and $16.5 million, respectively, of standby letters of credit issued under the credit facility with a financial institution, of which $0.6 million (A$0.6 million) and $5.9 million (A$5.1 million), respectively, were denominated in Australian dollars. In accordance with the terms of our credit facility, increases or decreases in the exchange rate between the Australian dollar and the U.S. dollar will increase or decrease the amount available to us under the credit facility.
	As of December 31, 2013, we had a $15.0 million unsecured surety bond. The surety bond provides a financial guarantee to support performance obligations under certain customer agreements. As of December 31, 2012, there was no surety bond outstanding. In the event any such letters of credit or surety bonds are called, we would be obligated to reimburse the issuer of the letter of credit or surety bond. We do not believe there will be any claims against currently outstanding letters of credit or surety bonds.
	Indemnification Commitments
	Directors, Officers and Employees. In accordance with our bylaws and/or pursuant to indemnification agreements we have entered into with directors, officers and certain employees, we have indemnification obligations to our directors, officers and employees for claims brought against these persons arising out of certain events or occurrences while they are serving at our request in such a capacity. We maintain a director and officer liability insurance coverage to reduce our exposure to such obligations, and payments made under these agreements. To date, there have been no indemnification claims by these directors, officers and employees.
	Customers and Third Party Device Manufacturers. Refer to the discussion above under the heading “Legal Contingencies” for a description of our indemnification obligations.
	Our contracts with customers and third party device manufacturers typically provide indemnification for claims filed by third parties alleging that our products and services sold to the customer or manufacturer infringe or misappropriate any patent, copyright, trademark or other intellectual property right.
	In our customer contracts, we also typically provide an indemnification for third-party claims resulting from death, personal injury or property damage caused by the negligence or willful misconduct of our employees and agents in connection with the performance of certain contracts.
	Under our customer and third party device manufacturer indemnities, we typically agree to defend the utility customer or third party device manufacturer, as the case may be, from such claims, and pay any resulting costs, damages and attorneys’ fees awarded against the indemnified party with respect to such claims, provided that (a) the indemnified party promptly notifies us in writing of the claim, (b) the indemnified party provides reasonable assistance to us at our expense, and (c) we have sole control of the defense and all related settlement negotiations.
	Insurance. We maintain various insurance coverages, subject to policy limits, that enable us to recover a portion of any amounts paid by us in connection with our obligation to indemnify our customers and third party device manufacturers. However, because our maximum liability associated with such indemnification obligations generally is not stated explicitly in the related agreements, and further because many states prohibit limitations of liability for such indemnified claims, the maximum potential amount of future payments we could be required to make under these indemnification provisions could significantly exceed insurance policy limits.
	Historically, payments made by us under these indemnification provisions have not had a material effect on our results of operations, financial position or cash flows.

Convertible_Preferred_Stock_an

Convertible Preferred Stock and Preferred Stock Warrants	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Convertible Preferred Stock and Preferred Stock Warrants	'
	7. CONVERTIBLE PREFERRED STOCK AND PREFERRED STOCK WARRANTS
	Convertible Preferred Stock
	Upon the closing of our IPO, all shares of our then-outstanding convertible preferred stock, as shown on the table below, automatically converted into shares of our common stock (see Note 1 Description of Business and Summary of Significant Accounting Policies, Initial Public Offering):
			Shares		Conversion			Shares			Conversion		Carrying		Aggregate
			Authorized		Price			Issued and			Ratio		Value		Liquidation
					Per Share			Outstanding			Per Share**				Preference
	Series A			4,800	$	4.7625			3,996			1	$	18,976	$	19,030
	Series A-1			420		4.7625			420			1		1,989		2,000
	Series B			6,085		1.8715			4,378			1		7,879		8,193
	Series C			7,933		7.5			6,849			1		49,176		51,365
	Series D			4,728		38.927			4,624			2.2899		89,643		180,000
	Series E			2,106		50			2,100			2.9412		103,062		120,750
				26,072					22,366	*			$	270,725	$	381,338
	*	Shares issued and outstanding does not total due to rounding.
	**	Based on our IPO price of $17.00 per share
	In connection with our IPO in March 2013, our previously authorized and outstanding convertible preferred stock was converted into 32,406,995 shares of common stock. Included in this amount were incremental shares issued to Series D and Series E preferred stockholders in accordance with their contractual conversion rights which stated that if the IPO conversion price for Series D and Series E preferred stockholders was below $38.927 and $50.00 per share, respectively, then we would issue to the eligible holders additional shares of common stock for no additional consideration pursuant to an automatic adjustment in our certificate of incorporation. The additional shares resulted in a beneficial conversion feature for Series E preferred stock and we recognized a $105.0 million deemed dividend to Series E preferred stockholders at the conversion date. This non-cash charge impacts net loss applicable to our common stockholders and basic and diluted net loss per share applicable to common stockholders.
	Shares of our preferred stock were not redeemable. However, since certain liquidation events (including a merger or acquisition or the sale of all or substantially all of our assets) were not solely within our control, the convertible preferred stock were classified outside of the stockholders’ deficit section of the balance sheets.
	Convertible Preferred Stock Warrants
	The following convertible preferred stock warrants were outstanding and fully vested as of December 31, 2012 and through the date prior to of our initial public offering (in thousands except per share data):
	Warrants to Purchase Convertible Preferred Stock		Price		Shares			Fair Value
			per Share
	Series A		$	4.7625		47		$	1,630
	Series C		$	7.5		333			9,627
	Series E		$	50		5			4
	Total					386	*	$	11,261
	*	Shares exercisable under outstanding warrants do not total due to rounding.
	Warrant Termination and Concurrent Private Placement with a Related Party
	Prior to our IPO, entities affiliated with Foundation Capital, together Foundation Capital, beneficially owned 32.7% of our common stock. Foundation Capital is considered a related party. Foundation Capital held warrants to purchase 41,993 shares of our Series A Preferred Stock and 333,333 shares of our Series C Preferred Stock prior to our IPO.
	All such warrants terminated immediately prior to the effectiveness of our IPO in exchange for the aggregate payment by us of $12.0 million to these entities. In connection with the transaction, we reduced our preferred stock warrant liability by $11.2 million and recorded a loss of $0.8 million in the year ended December 31, 2013.
	We also entered into a private placement purchase agreement whereby Foundation Capital purchased an aggregate of $12.0 million of shares of our common stock at the same price as the price offered to the public, or 705,881 shares based on the IPO price of $17.00 per share. This private placement purchase was consummated on the same day that our IPO closed.
	Conversion of Convertible Preferred Stock Warrants to Common Stock Warrants
	In connection with our IPO, the remaining warrants to purchase shares of Series A and Series E preferred stock converted into warrants to purchase 20,768 shares of our common stock, and we reclassified the related preferred stock warrant liability to additional paid-in capital.

Common_Stock

Common Stock	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Common Stock	'
	8. COMMON STOCK
	Restated Certificate of Incorporation and Amended and Restated Bylaws
	Our restated certificate of incorporation and amended and restated bylaws became effective upon the closing date of our IPO. Our restated certificate of incorporation: (a) eliminated the references to the terms of our existing series of preferred stock, which converted to common stock in connection with the IPO; (b) increased the authorized number of shares of common stock to 1,000,000,000 shares; (c) authorized 10,000,000 shares of undesignated preferred stock; (d) provided that holders of common stock will not be entitled to vote on amendments to the restated certificate that relate solely to the terms of any preferred stock designated by our Board of Directors if the holders of such preferred stock are entitled to vote on such amendment; (e) provided that our Board of Directors are classified into three classes of directors; (f) provided that at least two-thirds of the voting power of all of the then-outstanding shares of our capital stock is required to amend the bylaws; (g) provided that stockholders cannot call a special meeting of stockholders, act by written consent without a meeting, fill vacancies in the Board of Directors, remove a director other than for cause, or change the authorized number of directors; and (h) included certain other provisions customary for public companies.
	Equity Incentive Plan and Employee Stock Purchase Plan
	Our Board of Directors adopted the 2012 Equity Incentive Plan, or the 2012 Plan, which became effective on March 12, 2013 and serves as the successor to our 2003 Stock Option Plan, or the 2003 Plan. Pursuant to the 2012 Plan, 3,400,000 shares of our common stock were initially reserved for grant, plus (1) any shares that were reserved and available for issuance under the 2003 Plan at the time the 2012 Plan became effective, and (2) any shares that become available upon forfeiture or repurchase by us under the 2003 Plan and a stock option plan assumed in connection with a previous acquisition, will be reserved for issuance. Under the 2012 Plan, we may grant both incentive and non-statutory stock options, restricted stock and restricted stock units to employees, directors and service providers. We may grant options to purchase shares of common stock to employees, directors and service providers at prices not less than the fair market value at date of grant for both Incentive Stock Options, or ISOs or Nonqualified Stock Options, or NQSOs. ISO options granted to a person who, at the time of the grant, owns more than 10% of the voting power of all classes of stock must be at no less than 110% of the fair market value and expire five years from the date of grant. All other options generally have a contractual term of 10 years. Options generally vest over four years. Restricted stock units, or RSUs generally vest between two to four years. As of December 31, 2013 and 2012, there were 2.5 million and 3.0 million shares, respectively, of common stock reserved for future issuance under our stock plan.
	Our Board of Directors adopted the 2012 Employee Stock Purchase Plan, or ESPP, which became effective on March 12, 2013, pursuant to which 400,000 shares of our common stock have been reserved for future issuance. Eligible employees can enroll and elect to contribute up to 15% of their compensation through payroll withholdings in each offering period, subject to certain limitations. Each offering period is six months in duration, with the exception of the initial offering period which commenced in March 2013 upon the date our IPO was declared effective and that ended on February 14, 2014. The purchase price of the stock is the lower of 85% of the fair market value on (a) the first day of the offering period or (b) the purchase date.
	Common Stock Warrants
	In March 2011, we granted a warrant to purchase 50,000 shares of common stock at $0.005 per share. The warrant was immediately exercisable and non-forfeitable, and would have expired on the earlier of a change in control or March 31, 2016. The fair value of the warrant was determined to be $2.5 million based on the Black-Scholes-Merton option pricing model. We accounted for the warrant as an equity instrument and recorded the fair value as a general and administrative expense during the year ended December 31, 2011.
	The following assumptions were used in valuing the common stock warrant:
	Expected volatility		49	%
	Expected dividends		0	%
	Expected term in years		5
	Risk-free interest rate		2.2	%
	Fair value of common stock	$	50.25
	In connection with our IPO, warrants to purchase shares of our preferred stock converted into warrants to purchase 20,768 shares of our common stock, at a weighted average exercise price of $13.91 per share.
	As of December 31, 2013, we issued 57,370 shares of common stock pursuant to the net exercise of all of our common stock warrants.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	9. STOCK-BASED COMPENSATION
	We recorded stock-based compensation expense as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Cost of revenue	$	12,275		$	2,553		$	3,089
	Research and development		17,333			4,229			3,349
	Sales and marketing		7,060			2,822			2,425
	General and administrative		15,836			5,488			5,957
	Stock-based compensation expense	$	52,504		$	15,092		$	14,820
	We issue new common shares upon exercise of stock options. The following table summarizes our stock option activity and related information for the year ended December 31, 2013 (in thousands, except per share data):
		Options Outstanding
		Number of			Weighted			Weighted			Aggregate
		Shares			Average			Average			Intrinsic
					Exercise			Remaining			Value
					Price per			Contractual
					Share			Term (years)
	Balance at December 31, 2012		4,616		$	21.73
	Options granted		1,168			18.36
	Options exercised		(631	)		4.74
	Options cancelled or expired		(427	)		27.52
	Balance at December 31, 2013		4,726		$	11.88			6.43		$	43,146
	As of December 31, 2013:
	Options vested and expected to vest		4,651		$	11.76			6.38		$	42,988
	Options exercisable		3,382		$	9.39			5.41		$	39,267
	The aggregate intrinsic value disclosed above represents the total intrinsic value (the difference between the fair value of our common stock as of December 31, 2013 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on December 31, 2013. This amount is subject to change based on changes to the fair value of our common stock. During the years ended December 31, 2013, 2012, and 2011, the total cash received from the exercise of stock options was $2.9 million, $0.6 million, and $0.8 million, net of repurchases, respectively, and the total intrinsic value of stock options exercised was $9.5 million, $6.6 million, and $5.7 million, respectively.
	Restricted Stock Units
	The following table summarizes our restricted stock unit activity and related information for the year ended December 31, 2013 (in thousands, except per share data):
		Restricted Stock
		Units Outstanding
		Number of			Weighted
		Shares			Average Grant
					Date Fair Value
					per Share
	Balance at December 31, 2012		231		$	49.51
	Restricted stock units granted		3,662			18.41
	Restricted stock units vested		(1,019	)		23.36
	Restricted stock units cancelled		(115	)		19.69
	Balance at December 31, 2013		2,759		$	19.14
	The fair values of restricted stock units are determined based upon the fair value of the underlying common stock at the date of grant.
	Valuation of Employee Stock-Based Compensation
	We recognize compensation expense for stock-based awards based on their grant-date fair value on a straight-line basis over the service period for which such awards are expected to be outstanding. The fair value of stock options granted pursuant to our equity incentive plans is determined using the Black-Scholes-Merton option pricing model. The determination of fair value is affected by the estimates of our valuation, as well as assumptions regarding subjective and complex variables such as expected employee exercise and forfeiture behavior and our expected stock-price volatility over the expected term of the award. Generally, assumptions are based on historical information and judgment was required to determine if historical trends may be indicators of future outcomes. The fair value of each option grant is estimated on the date of grant.
	Prior to our IPO, our Board of Directors considered a broad range of factors to determine the fair value of our common stock at each meeting at which awards were approved. These factors included, but were not limited to, the prices for our convertible preferred stock sold to outside investors in arm’s-length transactions, the rights, preferences and privileges of our convertible preferred stock relative to those of our common stock, our operating and financial performance, the hiring of key personnel, the introduction of new products, our stage of development and revenue growth, the lack of an active public market for our common and preferred stock, industry information such as market growth and volume, the performance of similarly-situated companies in our industry, the execution of strategic and development agreements, the risks inherent in the development and expansion of our products and services, the prices of our common stock sold to outside investors in arm’s-length transactions, and the likelihood of achieving a liquidity event, such as an initial public offering or sale given prevailing market conditions and the nature and history of our business.
	We currently have no history or expectation of paying cash dividends on our common stock. We estimate the volatility of our common stock at the date of grant based on the historical and implied volatility of the stock prices of a peer group of publicly-traded companies for a period equal to the expected life of our stock options. The risk-free interest rate is based on the U.S. Treasury yield for a term consistent with the expected term of the awards in effect at the time of grant. The expected term represents the weighted-average period the stock options are expected to remain outstanding. The expected term is determined based on historical exercise behavior, post-vesting termination patterns, options outstanding and future expected exercise behavior.
	The following table summarizes the assumptions relating to our stock options:
		Year Ended December 31,
		2013			2012			2011
	Expected volatility		47% – 52	%		53	%		48% – 54	%
	Expected dividends		0	%		0	%		0	%
	Expected life in years		5.00 – 6.08			5.95 – 6.08			5.50 – 6.08
	Risk-free interest rate		0.87% – 1.96	%		1	%		1.4% – 2.7	%
	Weighted average grant date fair value per share	$	19.11		$	21.2		$	24.7
	The following table summarizes the assumptions relating to our ESPP:
	Expected volatility		52	%
	Expected dividends		0	%
	Expected life in years		< 1 year
	Risk-free interest rate		0.87	%
	In March 2013, as approved by our Board of Directors, we modified certain stock options held by employees and directors to purchase 1,752,895 shares of our common stock with an exercise price of $34.90 per share or greater to reduce the exercise price equal to $17.00 per share, the IPO price. There were no changes to vesting terms or conditions. We incurred an incremental charge to stock-based compensation expense of $4.7 million for year ended December 31, 2013, and expect to incur $1.3 million of incremental stock-based compensation expense related to the modification over a weighted average period of 1.2 years.
	As of December 31, 2013 there was $52.3 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements, which is expected to be recognized over a weighted-average period of 2.2 years. The total fair value on the respective vesting dates of restricted stock units during the years ended December 31, 2013, 2012 and 2011 was $19.5 million, $0.3 million and $0.0 million, respectively

Benefit_Plan

Benefit Plan	12 Months Ended
	Dec. 31, 2013
Compensation And Retirement Disclosure [Abstract]	'
Benefit Plan	'
	10. BENEFIT PLAN
	In 2003, our Board of Directors approved the adoption of a savings plan under Section 401(k) of the Internal Revenue Code of 1986, as amended (the “Code”). The plan covers eligible employees who elect to participate. We are allowed to make discretionary profit sharing and qualified non-elective contributions as defined by the Plan and as approved by the Board of Directors. We have not historically matched eligible participants’ 401(k) contributions. No discretionary profit sharing contributions have been made to date.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	11. INCOME TAXES
	The components of loss before income taxes are as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	United States	$	(28,774	)	$	(73,662	)	$	(83,050	)
	Foreign		(37,809	)		(15,665	)		(8,946	)
	Loss before income taxes	$	(66,583	)	$	(89,327	)	$	(91,996	)
	The provision (benefit) for income taxes consists of the following (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Current:
	United States federal	$	—		$	—		$	—
	State		(115	)		382			229
	Foreign		452			306			299
	Total current provision for income taxes		337			688			528
	Deferred:
	United States federal		(47	)		—			—
	State		123			—			(127	)
	Foreign		(189	)		(298	)		(38	)
	Total deferred provision (benefit) for income taxes		(113	)		(298	)		(165	)
	Provision for income taxes	$	224		$	390		$	363
	The provision for income taxes differs from the amount computed by applying the federal statutory income tax rate of 35% to loss before income taxes as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Federal statutory tax expense (benefit)	$	(23,304	)	$	(31,265	)	$	(32,199	)
	Research tax credit		(884	)		—			(486	)
	Effect of non-U.S. operations		13,320			5,469			3,321
	Change in valuation allowance		(925	)		23,732			27,843
	Stock-based compensation expense		3,455			2,665			2,718
	Remeasurement of preferred stock warrant liability		—			(752	)		(1,203	)
	Loss on debt extinguishments		8,287			—			—
	Other		275			541			369
	Provision for income taxes	$	224		$	390		$	363
	Deferred income taxes reflect the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The components of our deferred tax assets and liabilities are as follows (in thousands):
		December 31,
		2013			2012
	Deferred tax assets:
	Net operating loss and tax credit carryforwards	$	157,971		$	149,408
	Deferred revenue		96,054			100,380
	Stock-based compensation expense		11,415			6,202
	Warrant liability		—			32
	Accruals and reserves		5,793			4,849
	Intangible assets		1,480			1,532
	Other		343			65
	Gross deferred tax assets		273,056			262,468
	Valuation allowance		(168,092	)		(166,995	)
	Deferred tax assets		104,964			95,473
	Deferred tax liabilities
	Property and equipment, net		(1,905	)		(2,640	)
	Deferred cost of revenue		(102,459	)		(92,300	)
	Deferred tax liabilities		(104,364	)		(94,940	)
	Net deferred tax assets	$	600		$	533
	As of December 31, 2013, we had federal and state net operating loss carryforwards of $390.4 million and $365.4 million, respectively. Pursuant to section 382 of the Code, $41.4 million of the net operating loss carryforwards are subject to an annual limitation, which could affect the timing of the utilization of such carryforwards. If not utilized, the federal and state net operating loss carryforwards will begin to expire in 2027 and 2016, respectively. As of December 31, 2013, we had federal and California research tax credit carryforwards of $8.2 million and $9.0 million, respectively. The federal credit carryforwards will begin to expire in 2024, and the California credit carryforwards have no expiration date.
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. The valuation allowance increased by $1.1 million, $25.2 million and $30.5 million during the years ended December 31, 2013, 2012 and 2011, respectively.
	Undistributed earnings of our foreign subsidiaries amounted to $1.4 million as of December 31, 2013. Those earnings are considered to be indefinitely reinvested and, accordingly, no U.S. income taxes have been provided thereon. Upon distribution of those earnings in the form of dividends or otherwise, we would be subject to both U.S. income taxes (subject to an adjustment for foreign tax credits) and foreign withholding taxes. The income tax liability that might be incurred if these earnings were to be distributed is not material.
	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Unrecognized tax benefits—beginning of period	$	5,586		$	4,393		$	3,395
	Gross increase for tax positions of prior years		1,216			774			—
	Gross increase for tax positions of current year		1,913			419			998
	Unrecognized tax benefits balance—end of period	$	8,715		$	5,586		$	4,393
	As of December 31, 2013 all unrecognized tax benefits have been netted against the related deferred tax assets. Up to $7.1 million and $4.5 million of unrecognized tax benefits at December 31, 2013 and 2012, respectively, would reduce the effective income tax rate in future periods if recognized. However, one or more of these unrecognized tax benefits relate to deferred tax assets that could be subject to a valuation allowance if and when recognized in a future period, which could impact the timing and amount of any related effective tax rate benefit.
We recognize interest and penalties related to uncertain tax positions in income tax expense. To the extent accrued interest and penalties do not ultimately become payable, amounts accrued will be reduced and reflected as a reduction of the provision for income taxes in the period that such determination is made. Due to our net operating loss position, we have not recorded interest and penalties related to uncertain tax positions as of December 31, 2013.
We file income tax returns in the United States, including various states, and certain foreign jurisdictions. The tax years 2002 to 2013 remain open to examination by the major taxing jurisdictions in which we are subject to tax. As of December 31, 2013, we were not under examination by the Internal Revenue Service or any state or foreign tax jurisdiction.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Information	'
	12. SEGMENT INFORMATION
	We operate in one reportable segment. Our chief operating decision maker is our Chief Executive Officer, who reviews consolidated operating results to make decisions about allocating resources and assessing performance for the entire company. Revenue by geography is based on the billing address of the utility customer. The following table presents revenue by geographic region (in thousands):
		Year Ended December 31,
		2013		2012		2011
	Revenue:
	United States	$	285,430	$	181,948	$	225,564
	Australia		40,939		13,905		5,664
	All Other		489		884		5,822
	Total	$	326,858	$	196,737	$	237,050
	Substantially all of our long-lived assets are located in the United States.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Selected Quarterly Financial Data	'
	13. Selected Quarterly Financial Data (unaudited)
	The following tables set forth selected unaudited quarterly statements of operations data for each of the last eight quarters in the years ended December 31, 2013 and 2012 (in thousands, except per share data).
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,			December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013			2012			2012			2012			2012
	Revenue, net	$	97,164		$	72,481		$	103,510		$	53,703		$	50,071		$	39,628		$	51,584		$	55,454
	Cost of revenue		63,420			49,255			55,260			43,569			39,523			35,194			44,914			45,387
	Gross profit		33,744			23,226			48,250			10,134			10,548			4,434			6,670			10,067
	Operating expenses		33,792			35,341			38,268			49,708			30,735			28,901			28,961			31,766
	Operating income (loss)		(48	)		(12,115	)		9,982			(39,574	)		(20,187	)		(24,467	)		(22,291	)		(21,699	)
	Other income (expense), net		138			(54	)		(184	)		(24,728	)		(902	)		(2,028	)		(1,078	)		3,325
	Income (loss) before income taxes		90			(12,169	)		9,798			(64,302	)		(21,089	)		(26,495	)		(23,369	)		(18,374	)
	Provision for income taxes		(268	)		100			328			64			(79	)		373			38			58
	Net income (loss)		358			(12,269	)		9,470			(64,366	)		(21,010	)		(26,868	)		(23,407	)		(18,432	)
	Deemed dividend to convertible preferred stockholders		—			—			—			(105,000	)		—			—			—			—
	Net income (loss) attributable to common stockholders	$	358		$	(12,269	)	$	9,470		$	(169,366	)	$	(21,010	)	$	(26,868	)	$	(23,407	)	$	(18,432	)
	Net income (loss) per share attributable to common stockholders:
	Basic	$	0.01		$	(0.26	)	$	0.2		$	(16.18	)	$	(5.65	)	$	(7.30	)	$	(6.38	)	$	(5.06	)
	Diluted	$	0.01		$	(0.26	)	$	0.19		$	(16.18	)	$	(5.65	)	$	(7.30	)	$	(6.38	)	$	(5.06	)
	Weighted average shares used to compute net income (loss) per share attributable to common stockholders:
	Basic		47,198			46,729			46,599			10,469			3,720			3,682			3,669			3,641
	Diluted		49,603			46,729			48,995			10,469			3,720			3,682			3,669			3,641

Description_of_Business_and_Su1

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Reverse Stock Split	'
	Reverse Stock Split
	Prior to our Initial Public Offering (“IPO”), our Board of Directors and holders of the requisite number of outstanding shares of our capital stock approved an amendment to our restated certificate of incorporation to effect a 5-for-1 reverse stock split of our outstanding capital stock. The reverse stock split was effected on February 11, 2013. The reverse stock split did not result in an adjustment to par value. The reverse stock split is reflected in the accompanying consolidated financial statements and related notes on a retroactive basis for all periods presented.
Initial Public Offering	'
	Initial Public Offering
	In March 2013, we completed our IPO in which we issued and sold 5,462,500 shares of common stock at a public offering price of $17.00 per share. We received net proceeds of $84.2 million after deducting underwriting discounts and commissions of $6.5 million and paid offering costs in the year ended December 31, 2013 of $2.2 million, but before deducting previously paid offering expenses of approximately $4.2 million. Concurrently with our IPO, we issued and sold in a private placement 705,881 shares of common stock at the public offering price of $17.00 per share, which resulted in net proceeds of $12.0 million. In addition, in connection with our IPO:
		•		All of our outstanding convertible preferred stock converted into 32,406,995 shares of common stock.
		•		Our $24.0 million and $30.0 million convertible notes together with contractual accrued interest of $2.3 million converted into 3,764,954 shares of common stock. In connection with the conversion, we recorded a loss on debt extinguishments of $22.9 million. Please see Note 5 Borrowings for further discussion on the conversion features of the convertible notes, the calculation of the number of shares into which the notes were converted and the accounting for debt extinguishment.
		•		We reduced our preferred stock warrant liability by $11.2 million and recorded a loss of $0.8 million in the year ended December 31, 2013 resulting from our payment of $12.0 million as consideration for the termination of certain warrants to purchase shares of Series A preferred stock and all warrants to purchase shares of Series C preferred stock, which occurred immediately prior to the effectiveness of our IPO. Please see Note 7 Convertible Preferred Stock and Preferred Stock Warrants.
		•		We reclassified the preferred stock warrant liability for the surviving warrant to purchase shares of Series A preferred stock and all warrants to purchase shares of Series E preferred stock to additional paid-in capital, as these warrants converted to warrants to purchase shares of common stock. Please see Note 7 Convertible Preferred Stock and Preferred Stock Warrants.
		•		We recognized stock-based compensation expense of $4.4 million in the year ended December 31, 2013 upon the issuance of 87,507 shares of common stock following the vesting upon the effectiveness of the Registration Statement on Form S-1 of 87,507 restricted stock units previously granted in connection with our incentive bonus plans. Please see below—Corporate Bonus Incentive Plan for further discussion of this stock-based compensation expense.
		•		We recognized stock-based compensation expense of $10.2 million in the year ended December 31, 2013 upon the issuance of 602,274 shares of common stock following the granting upon the effectiveness of the Registration Statement on Form S-1 of 602,274 fully vested restricted stock units in connection with our incentive bonus plans. Please see below—Corporate Bonus Incentive Plan for further discussion of this stock-based compensation expense.
		•		We recognized stock-based compensation expense of approximately $4.7 million in the year ended December 31, 2013 related to the modification of stock options held by current employees. Please see Note 9 Stock-Based Compensation for further discussion of this stock-based compensation expense.
		•		We reclassified $6.4 million of deferred issuance costs previously recorded in other long-term assets as an off-set to the equity proceeds in connection with our IPO.
Accounting Principles and Basis of Presentation	'
	Accounting Principles and Basis of Presentation
	The consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP. The consolidated financial statements include the accounts of Silver Spring Networks, Inc. and its wholly owned subsidiaries. Intercompany balances and transactions have been eliminated in consolidation.
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, contingent assets and liabilities, and revenue and expenses during the reporting period. Estimates are used for revenue and cost recognition, inventory valuation, warranty obligations, preferred stock warrants and embedded derivatives valuations, stock-based compensation, classification of current and non-current deferred revenue and deferred cost of revenue, income taxes and deferred income tax assets and associated valuation allowances. These estimates generally involve complex issues and require judgments, involve the analysis of historical and prediction of future trends, can require extended periods of time to resolve and are subject to change from period to period. Actual results may differ materially from management’s estimates.
Cash, Cash Equivalents and Short-term Investments	'
	Cash, Cash Equivalents and Short-term Investments
	Cash equivalents consist of highly liquid investments with insignificant interest rate risk and original or remaining maturities at the time of purchase of three months or less, and consist of money market funds. Short-term investments consist of high investment grade securities with original or remaining maturities at the time of purchase of greater than three months, and are available for use in current operations. We classify all of our cash equivalents and short-term investments as available-for-sale, which are recorded at fair value. Unrealized gains and losses are included in accumulated other comprehensive income (loss) in stockholders’ deficit. Realized gains and losses are included in other income and expense, net. Determining whether a decline in fair value is other-than-temporary requires management judgment based on the specific facts and circumstances of each security. We evaluate our short-term investments for impairment each reporting period. Amounts are reclassified out of accumulated other comprehensive income (loss) into earnings using the specific identification method.
Inventory	'
	Inventory
	Inventory is stated at the lower of cost or market. Cost is computed using standard cost, which approximates actual cost on a first-in, first-out basis. The determination of market value involves numerous judgments including estimated average selling prices based upon recent sales volumes, industry trends, existing customer orders and current contract prices. We evaluate our ending inventories for excess quantities and obsolescence based on forecasted demand within specific time horizons, technological obsolescence, and an assessment of any inventory that is not of saleable condition. Forecasted demand requires management estimates and is subject to several uncertainties including market and economic conditions, technology changes and new product introductions. Actual demand may differ from forecasted demand, and such differences may have a material effect on recorded inventory values and operating results.
	In addition, we enter into purchase commitments with third-party contract manufacturers to manage lead times and meet product forecasts and with other parties to purchase various key components used in the manufacture of our products. Accruals are established for estimated losses on purchased components for which we believe it is probable that they will not be recoverable in future operations. To the extent that such forecasts are not achieved, commitments and associated accruals may change.
Revenue Recognition	'
	Revenue Recognition
	We generally market our products and services for our advanced metering, distribution automation and demand-side management solutions directly to customers. For our advanced metering solution, we contract with third-party device manufacturers, which integrate our communications modules into their meters. Our advanced metering solution, which includes our UtilOS network operating system, UtilityIQ software suite, networking hardware, and communications modules, provides utilities with two-way communication from our communications modules to the utility’s back office. Our hardware devices include UtilOS embedded software, which functions together with the tangible hardware elements to deliver the tangible products’ essential functionality. Our UtilityIQ software suite of products includes software that is not embedded with the tangible hardware elements, but that is also necessary to deliver the tangible products’ essential network functionality, as well as other application software that provides additional functionality to the network solution. We derive revenue from sales of products, including hardware and software, as well as services, including network design and deployment support, managed services and SaaS, and ongoing customer support. We enter into separate arrangements with third party device manufacturers to integrate our communications modules with their meters pursuant to our customers’ specifications. While we may receive payment directly from these third party device manufacturers, the timing of revenue recognition related to communications modules delivered to third party device manufacturers is ultimately determined based upon acceptance by our customers. Substantially all of our sales of communications modules have been fulfilled through third party device manufacturers in this manner.
	We enter into multiple deliverable arrangements with customers to deploy our networking platform and solutions, which include the delivery of hardware and software, as well as services.
	Judgment is required in determining the separate units of accounting, which depends on whether the delivered items have standalone value to customers. When we sell or could sell our products and services separately, or when the customer could resell them on a standalone basis, we treat the delivered elements as having standalone value. In our typical customer arrangements, we consider the following to be separate units of accounting: our hardware together with the related embedded software; our network management software; and our service offerings, which include professional services, managed services and SaaS, and ongoing customer support.
	We determine total arrangement consideration, and exclude amounts that are contingent upon the delivery of additional items or meeting other specified performance conditions, including potential refunds or penalty provisions. We allocate the total arrangement consideration to the deliverables based on our determination of the units of accounting and their relative selling prices. As we have not yet established vendor-specific objective evidence or VSOE or identified third-party evidence of fair value for these units of accounting, we use our best estimate of selling price to perform the relative fair value allocation. Judgment is also required in determining how to measure and allocate arrangement consideration among the separate units of accounting. The process for performing an assessment of our best estimate of selling price for our products and services is based on quantitative and qualitative aspects of multiple factors. These factors include market conditions, such as competitive alternatives and pricing practices, as well as company-specific factors, such as standalone sales, nature and size of the customer, contractually stated prices, costs to manufacture products or provide services and profit objectives. In establishing such profit objectives, we consider prices in previous contracts, size of the transaction, and the drivers, if any, that could influence future margins.
	The following revenue recognition criteria are applied to the units of accounting in all utility customer arrangements, as well as those in which orders of communications modules are fulfilled through third party device manufacturers as described above. We do not recognize revenue for a unit of accounting until all of the following criteria have been met:
		•		Persuasive evidence of an arrangement exists. Binding contracts or purchase orders are used to determine the existence of an arrangement.
		•		Delivery has occurred. Shipping documents and customer acceptance provisions, where applicable, are used to verify delivery.
		•		The fee is fixed or determinable. We assess whether the fee is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment.
		•		Collectibility is reasonably assured. We assess collectibility based primarily on creditworthiness of the customer or third party device manufacturer as determined by credit assessments and payment history.
	Substantially all of our customer arrangements include acceptance provisions that require testing of the network against specific performance criteria. We consider the following factors in our assessment of whether the acceptance provisions are substantive:
		•		whether the criteria are based on our standard performance criteria or are customer-specific;
		•		our experience with similar types of arrangements or products, as well as our experience with the specific customer;
		•		whether we would be successful in enforcing a claim for payment even in the absence of acceptance confirmation from the customer;
		•		the nature and complexity of the acceptance testing, including the planned duration of the acceptance period; and
		•		the significance of financial penalties, if any, associated with not meeting performance criteria.
	Considering our limited historical experience to date, we have concluded for our current arrangements that the acceptance provisions are substantive. When we consider acceptance provisions to be substantive, revenue is not recognized until we have determined acceptance is achieved. Once we have achieved acceptance, we recognize revenue as follows:
		•		Revenue from software that functions together with the tangible hardware elements to deliver the tangible products’ essential functionality is recognized upon delivery assuming all other revenue recognition criteria are met. Revenue from application software and related software elements which are not considered essential to the functionality of hardware devices is recognized ratably over the longest service period for post-contract customer support or PCS and professional services as we have not established VSOE for software or the related software elements.
		•		Revenue from our service offerings, including professional services such as network design and deployment support, managed services and SaaS, and ongoing customer support is recognized as services are delivered or on a proportional performance basis depending on the underlying pattern of performance.
		•		Revenue from hardware is recognized when title transfers.
	Amounts that are invoiced prior to a transaction meeting all of the above revenue recognition criteria, including customer acceptance criteria, are recorded in deferred revenue until such criteria are satisfied. For all periods presented herein, the amount and timing of revenue and product cost recognition has been, and for the near-term will be, dependent primarily on our ability to meet substantive customer acceptance criteria. We consider a variety of factors in estimating the timing of customer acceptance, which includes contractual milestones, project schedules, availability of resources, the nature and extent of remaining testing cycles, and other relevant information provided by our project management team. Accordingly, we expect that the timing of recognition of revenue and related product costs on both a quarterly and annual basis will not be easily predictable. In addition, it is possible that the amount of current deferred revenue and related deferred cost of revenue reflected as of a balance sheet date will be significantly higher or lower than the amount of deferred revenue and related deferred cost of revenue that is ultimately recognized as revenue and cost of revenue within the 12 months following the balance sheet date. We classify deferred revenue and deferred cost of revenue that we expect to recognize during the 12 months following the balance sheet date as current deferred revenue and current deferred cost of revenue on our balance sheet and the remainder as non-current deferred revenue and non-current deferred cost of revenue.
	Certain of our customer and third party device manufacturer contracts include contingency provisions, which impact our revenue recognition as such contingent amounts limit the amount of the total arrangement consideration under multiple deliverable contracts that can be allocated to delivered and accepted products and services. These provisions include penalties for late delivery, liquidated damages related to failure to meet milestones or deliver specified products or services, or credits to be issued upon the failure to meet service level arrangements. The amounts that could be paid under these provisions are typically limited and capped at amounts that do not exceed the maximum contract value. Accordingly, even in situations where we have received customer acceptance, we limit the revenue recognized for accepted products and services by the amount that could be paid under these provisions. We do not recognize these deferred amounts until the provisions have lapsed.
	In cases where we sell third-party products and services such as meters, hardware, services, software or software maintenance as part of the overall solution, we evaluate whether we act as principal or agent under the arrangement. The evaluation considers multiple factors, including whether we are the primary obligor under the arrangement with the utility customer, whether we bear the risk of loss and credit risk associated with the supply of third-party products and services, whether we have the ability to change the product or perform part of the service, and whether we have the ability to control the price charged to our customers for the third-party products and services. Revenue is presented on a gross basis when we conclude that we are the principal under the arrangement with respect to third-party products and services, and revenue is presented on a net basis when we conclude that we are acting as the agent. The majority of our revenue related to third-party products and services is recognized on a gross basis as we are generally acting as the principal under our arrangements.
	Shipping charges billed to customers were not significant for the years ended December 31, 2013, 2012, and 2011. Shipping charges are included in revenue, and the related shipping costs are included in cost of revenue in the accompanying consolidated statements of operations.
Cost of Revenue	'
	Cost of Revenue
	Cost of product revenue includes contract manufacturing costs, including raw materials, components and associated freight, and normal yield loss. In addition, cost of product revenue includes compensation, benefits and stock-based compensation provided to our manufacturing personnel, overhead and other direct costs. Product costs are deferred upon shipment and are recognized in the period in which we recognize the related revenue. Period costs, which consist primarily of logistics costs, manufacturing ramp-up costs, expenses for inventory obsolescence, standard warranty costs and lower of cost or market adjustments are recognized in the period in which they are incurred.
	Costs of providing services include personnel-related costs, depreciation and amortization, and software hosting costs. Costs of providing services are not deferred and are included in cost of revenue in the period in which they are incurred. Accordingly, there are no deferred service costs of revenue in the accompanying balance sheets.
Deferred Revenue and Deferred Cost of Revenue	'
	Deferred Revenue and Deferred Cost of Revenue
	Deferred revenue results from transactions where we have billed the customer for product shipped or services performed but all revenue recognition criteria have not yet been met.
	Deferred cost of revenue is recorded for products for which ownership (typically title and risk of loss) has transferred to the customer, but for which criteria for revenue recognition have not been met. We only defer tangible direct costs associated with hardware products delivered. Cost of revenue for providing services is not deferred, but is expensed in the period incurred. Deferred cost of revenue associated with deferred product revenue is recorded at the standard inventory cost at the time of shipment. We evaluate deferred cost of revenue for recoverability based on multiple factors, including whether net revenues less related direct costs will exceed the amount of deferred cost of revenue based on the terms of the overall arrangement. To the extent that deferred cost of revenue is determined to be unrecoverable, we adjust deferred cost of revenue with a charge to product cost of revenue in the current period. In connection with our recoverability assessments, we have not incurred significant impairment charges through December 31, 2013.
	We recognize deferred revenue and associated deferred cost of revenue once all revenue recognition criteria have been met.
Product Warranty	'
	Product Warranty
	We provide warranties for substantially all of our products. Our standard warranty period extends from one to five years. We accrue for costs of standard warranty at the time of product shipment, and record changes in estimates to warranty accruals when it is probable a liability has been incurred and the amount of loss can be reasonably estimated.
	At the time of product shipment, we estimate and accrue for the amount of standard warranty cost and record the amount as a cost of revenue. Determining the amount of warranty costs requires management to make estimates and judgments based on historical claims experience, industry benchmarks, test data and various other assumptions including estimated field failure rates that are believed to be reasonable under the circumstances. The amount of warranty costs accrued are net of warranty obligations to be fulfilled by our suppliers. The results of these judgments formed the basis for our estimate of the total charge to cover anticipated customer warranty, repair, return and replacement and other associated costs. Should actual product failure rates, claim levels, material usage or supplier warranties on parts used in our products differ from our original estimates, revisions to the estimated warranty liability could result in adjustments to our cost of revenue in future periods.
	Certain of our standard product warranty obligations require us to reimburse a customer for installation and other related costs in the event that field reliability rates fall below contractually specified thresholds. We consider the probability that we will have to pay such incremental warranty costs based on the expected performance of a delivered product when we record new warranty obligations issued in a period as well as when we determine if any changes are required to our original estimates for pre-existing warranty obligations.
	Our warranty obligations are affected by product failure rates, claims levels, material usage and supplier warranties on parts included in our products. Because our products are relatively new and we do not have the benefit of long-term experience observing products’ performance in the field, it is possible that the estimates of a product’s lifespan and incidence of claims could vary from period to period.
	In certain customer arrangements, we have provided extended warranties for periods of up to 15 years following the initial standard warranty period. We recognize revenue associated with extended warranties over the extended warranty period when the extended warranty period commences. Costs associated with providing extended warranties are expensed as incurred during the extended warranty period.
Supplier Concentrations and Other Inventory Risks	'
	Supplier Concentrations and Other Inventory Risks
	We have arrangements under which substantially all of our manufacturing activity is subcontracted to third-party vendors. Currently our sole manufacturing relationship is with Plexus Corp., who provides us with a wide range of operational and manufacturing services, including material procurement, final assembly, test quality control, warranty repair, and shipment to our customers and third-party vendors. Contract manufacturing activities are conducted in the United States and are undertaken based on management’s product demand forecasts. Our contract manufacturer procures components necessary to assemble the products anticipated by management’s forecast and test the products according to our quality specifications. If the components are unused for specified periods of time, we may incur carrying charges or obsolete material charges for components that our contract manufacturers purchased to build products to meet our product demand forecasts. Our communications modules and other hardware products consist of commodity parts and certain custom components. Our components are generally available from multiple sources or suppliers. However, some components used in our products are purchased from single or limited sources.
	Finished goods are reported as inventory until title transfers to the customer. Consigned finished goods inventory that is maintained at customer locations is also reported as inventory until consumption or acceptance of the product by the customer. We account for consigned inventory on a first-in, first-out basis and record lower of cost or market or obsolete material charges when appropriate.
Concentration of Credit and Customer Risks	'
	Concentration of Credit and Customer Risks
	Our sales are currently concentrated with a small group of customers and third party device manufacturers principally located in the United States and Australia. In evaluating customer concentration risk, we attribute revenue to our customers, including amounts billed to third party device manufacturers for our communications modules.
	The following table summarizes the percentage of revenue related to our customers’ deployments in excess of 10% of total revenue:
			Year Ended December 31,
			2013			2012			2011
	PG&E			39	%		30	%		34	%
	FPL			20			31			26
	OG&E			—			18			—
	SMUD			—			—			12
	Each of these total revenue percentages includes amounts related to the customers’ deployments that were billed directly to our third party device manufacturers, as well as direct revenue from the customers. We typically extend credit to our customers and third party device manufacturers and do not require collateral or other security in support of accounts receivable. We attempt to mitigate the credit risk in our trade receivables through our credit evaluation process and payment terms. We analyze the need to reserve for potential credit losses and record allowances for doubtful accounts when necessary. To date, we have not had any significant write-offs of uncollectible accounts receivable, and there was no allowance for doubtful accounts as of December 31, 2013 and 2012.
	The following table summarizes the percentage of accounts receivable from customers and third party device manufacturers in excess of 10% of accounts receivable:
			December 31,
			2013			2012
	Baltimore Gas and Electric Company			26	%		26	%
	Landis + Gyr AG (acquired by Toshiba Corporation)			11			—
	Commonwealth Edison Company			10			—
	Virginia Electric and Power Company			10			—
	Secure Meters			—			16
	Progress Energy			—			15
	General Electric Company			—			10
Advertising Costs	'
	Advertising Costs
	We expense advertising costs as incurred. Advertising costs were $2.2 million, $2.5 million, and $2.5 million for each of the years ended December 31, 2013, 2012, and 2011.
Property and Equipment, Net	'
	Property and Equipment, Net
	Property and equipment are stated at cost. Depreciation is calculated using the straight-line method over the following estimated useful lives:
	Software		3 to 7 years
	Computer and network equipment		2 to 5 years
	Machinery and equipment		3 to 5 years
	Furniture and fixtures		5 to 7 years
	Leasehold improvements		Lesser of the lease term or the estimated useful lives of the improvements, generally 1 to 4 years
Long-Lived Assets	'
	Long-Lived Assets
	We evaluate long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. For the years ended December 31, 2013, 2012, and 2011, no impairment losses were recorded.
Research and Development	'
	Research and Development
	Research and development costs are expensed as incurred. Under our current practice of developing new products, technological feasibility of the underlying software is not established until substantially all product development and testing is complete, which generally includes the development of a working model. Our products are released within a short period of time after achieving technological feasibility.
Deferred Issuance Costs	'
	Deferred Issuance Costs
	Costs directly associated with the planned issuance of equity or debt instruments are capitalized and recorded as deferred issuance costs until the issuance of such instruments. Costs directly associated with debt instruments are capitalized as deferred issuance costs and amortized over the contractual term of the debt instrument utilizing the effective interest method. Deferred issuance costs included in other long-term assets were $5.0 million as of December 31, 2012. In connection with our IPO, deferred issuance costs previously recorded in other long-term assets were recorded as an off-set to the equity proceeds. As of December 31, 2013, there were no deferred issuance costs.
Corporate Bonus Incentive Plan	'
	Corporate Bonus Incentive Plan
	Our corporate bonus incentive plan is funded by a combination of cash and restricted stock units, at management’s discretion. The restricted stock units granted prior to our IPO contained a performance-based condition and vested upon the effectiveness of the Registration Statement on Form S-1. As a result, we recorded the related stock-based compensation for these awards in the year ended December 31, 2013 (as discussed above—Initial Public Offering). Subsequent to our IPO, we accrue and record the related stock-based compensation for corporate bonus amounts payable under this plan in connection with the period in which it is earned.
Stock-Based Compensation	'
	Stock-Based Compensation
	We measure and recognize compensation expense for all stock-based awards made to employees and directors, including stock options, restricted stock, restricted stock units, and employee stock purchase plan, based on estimated fair values. The fair values of stock options and our 2013 Employee Stock Purchase Plan (please refer to Note 9 Stock Based Compensation for further discussion) are estimated at the date of grant using the Black-Scholes-Merton option pricing model, which includes assumptions for the dividend yield, expected volatility, risk-free interest rate, and expected life. The fair values of restricted stock and restricted stock units are determined based upon the fair value of the underlying common stock at the date of grant. We expense stock-based compensation, adjusted for estimated forfeitures, using the straight-line method over the vesting term of the award. Our excess tax benefits cannot be credited to stockholders’ equity until the deduction reduces cash taxes payable; accordingly, we realized no excess tax benefits during any of the periods presented in the accompanying financial statements. The amount of capitalized stock-based employee compensation cost as of December 31, 2013 and 2012 was not material
Preferred Stock Warrant Liability	'
	Preferred Stock Warrant Liability
	We accounted for freestanding warrants to purchase shares of our convertible preferred stock as a liability on the consolidated balance sheets. The convertible preferred stock warrants were recorded as a liability because the underlying shares of convertible preferred stock were contingently redeemable and, therefore, could have obligated us to transfer assets at some point in the future (see Note 7 Convertible Preferred Stock and Preferred Stock Warrants). The warrants were recorded at fair value upon issuance and were subject to remeasurement to fair value at each balance sheet date, with any change in fair value recognized as a component of other income (expense), net, on the consolidated statements of operations. In connection with our IPO, we reduced our preferred stock warrant liability by $11.2 million and recorded a loss of $0.8 million in the year ended December 31, 2013 resulting from our payment of $12.0 million as consideration for the termination of certain warrants to purchase shares of Series A preferred stock and all warrants to purchase shares of Series C preferred stock, which occurred immediately prior to the effectiveness of our IPO. We reclassified the preferred stock warrant liability for the surviving warrant to purchase shares of Series A preferred stock and all warrants to purchase shares of Series E preferred stock to additional paid-in capital, as these warrants converted to warrants to purchase shares of common stock. As of December 31, 2013, there were no longer any preferred stock warrants outstanding.
Income Taxes	'
	Income Taxes
	Income taxes are calculated using the asset and liability method. Deferred income taxes are recorded for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. We record a valuation allowance to reduce our deferred tax assets to the amount of future tax benefit that we believe is more likely than not to be realized.
	We follow a two-step approach to recognizing and measuring tax benefits associated with uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if, based on the technical merits, it is more likely than not that the tax position will be sustained upon examination by a taxing authority, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement with a taxing authority. We recognize any interest and penalties related to uncertain tax positions in the provision for income taxes line of our consolidated statements of operations.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740)-Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The standard requires us to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss (NOL) carryforward or other tax credit carryforward when settlement in this manner is available under applicable tax law. We early adopted this guidance during the year ended December 31, 2013. The adoption of this guidance did not have a material impact on our consolidated financial statements.
	In February 2013, the FASB issued Accounting Standards Update No. 2013-02, Comprehensive Income (Topic 220)-Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. The standard requires entities to present (either on the face of the income statement or in the notes) the effects on the line items of the income statement for amounts reclassified out of accumulated other comprehensive income. We adopted this guidance on January 1, 2013, and the adoption did not have an impact on our consolidated financial statements.
Net Loss Per Share	'
	Basic net loss per share applicable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share applicable to common stockholders is computed by giving effect to all potential shares of common stock, including convertible debt, stock options, warrants and convertible preferred stock, to the extent dilutive. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential common shares outstanding would have been anti-dilutive.
Fair Value Measurements	'
	We measure certain financial assets and liabilities at fair value on a recurring basis.
	The measurements of fair value were established based on a fair value hierarchy that prioritizes the inputs. This hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The fair value framework requires the categorization of assets and liabilities into three levels based upon the assumptions (inputs) used to price the assets or liabilities. The guidance for fair value measurements requires that assets and liabilities carried at fair value be classified and disclosed in one of the following categories:
	Level 1—Quoted (unadjusted) prices in active markets for identical assets or liabilities.
	Level 2—Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability.
	Level 3—Unobservable inputs in which there is little or no market data, which requires us to develop our own assumptions. Our Level 3 liabilities consist of warrants to purchase convertible preferred stock and embedded derivatives related to our convertible promissory notes.
	Level 1 measurements are obtained from real-time quotes for transactions in active exchange markets involving identical assets. Level 2 measurements are obtained from readily available pricing sources for comparable instruments, identical instruments in less active markets, or models using market observable inputs. We did not have any transfers of financial instruments between valuation levels during the year ended December 31, 2013.
Operating and Capital Leases	'
	Our primary operating lease commitment at December 31, 2013, related to our headquarters in Redwood City, California, requires monthly lease payments through December 2016. We recognize rent expense on a straight-line basis over the lease period. Where leases contain escalation clauses, rent abatements, or concessions, such as rent holidays and landlord or tenant incentives or allowances, we apply them in the determination of straight-line rent expense over the lease term.
Valuation of Employee Stock-Based Compensation	'
	We recognize compensation expense for stock-based awards based on their grant-date fair value on a straight-line basis over the service period for which such awards are expected to be outstanding. The fair value of stock options granted pursuant to our equity incentive plans is determined using the Black-Scholes-Merton option pricing model. The determination of fair value is affected by the estimates of our valuation, as well as assumptions regarding subjective and complex variables such as expected employee exercise and forfeiture behavior and our expected stock-price volatility over the expected term of the award. Generally, assumptions are based on historical information and judgment was required to determine if historical trends may be indicators of future outcomes. The fair value of each option grant is estimated on the date of grant.
	Prior to our IPO, our Board of Directors considered a broad range of factors to determine the fair value of our common stock at each meeting at which awards were approved. These factors included, but were not limited to, the prices for our convertible preferred stock sold to outside investors in arm’s-length transactions, the rights, preferences and privileges of our convertible preferred stock relative to those of our common stock, our operating and financial performance, the hiring of key personnel, the introduction of new products, our stage of development and revenue growth, the lack of an active public market for our common and preferred stock, industry information such as market growth and volume, the performance of similarly-situated companies in our industry, the execution of strategic and development agreements, the risks inherent in the development and expansion of our products and services, the prices of our common stock sold to outside investors in arm’s-length transactions, and the likelihood of achieving a liquidity event, such as an initial public offering or sale given prevailing market conditions and the nature and history of our business.
	We currently have no history or expectation of paying cash dividends on our common stock. We estimate the volatility of our common stock at the date of grant based on the historical and implied volatility of the stock prices of a peer group of publicly-traded companies for a period equal to the expected life of our stock options. The risk-free interest rate is based on the U.S. Treasury yield for a term consistent with the expected term of the awards in effect at the time of grant. The expected term represents the weighted-average period the stock options are expected to remain outstanding. The expected term is determined based on historical exercise behavior, post-vesting termination patterns, options outstanding and future expected exercise behavior.
Segment Information	'
	We operate in one reportable segment. Our chief operating decision maker is our Chief Executive Officer, who reviews consolidated operating results to make decisions about allocating resources and assessing performance for the entire company. Revenue by geography is based on the billing address of the utility customer.

Description_of_Business_and_Su2

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of Percentage of Revenue Related to Customers' Deployments in Excess of Ten Percent of Total Revenue	'
	The following table summarizes the percentage of revenue related to our customers’ deployments in excess of 10% of total revenue:
		Year Ended December 31,
		2013			2012			2011
	PG&E		39	%		30	%		34	%
	FPL		20			31			26
	OG&E		—			18			—
	SMUD		—			—			12
Schedule of Percentage of Accounts Receivable from Customers and Third Party Device Manufacturers in Excess of Ten Percent of Accounts Receivable	'
	The following table summarizes the percentage of accounts receivable from customers and third party device manufacturers in excess of 10% of accounts receivable:
		December 31,
		2013			2012
	Baltimore Gas and Electric Company		26	%		26	%
	Landis + Gyr AG (acquired by Toshiba Corporation)		11			—
	Commonwealth Edison Company		10			—
	Virginia Electric and Power Company		10			—
	Secure Meters		—			16
	Progress Energy		—			15
	General Electric Company		—			10
Property and Equipment Estimated Useful Lives	'
	Depreciation is calculated using the straight-line method over the following estimated useful lives:
	Software	3 to 7 years
	Computer and network equipment	2 to 5 years
	Machinery and equipment	3 to 5 years
	Furniture and fixtures	5 to 7 years
	Leasehold improvements	Lesser of the lease term or the estimated useful lives of the improvements, generally 1 to 4 years

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Computation of Historical Basic and Diluted Net Loss Per Share	'
	The following table sets forth the computation of historical basic and diluted net loss per share (in thousands, except per share data):
		Year Ended December 31,
		2013			2012			2011
	Net loss	$	(66,807	)	$	(89,717	)	$	(92,359	)
	Deemed dividend to convertible preferred shareholders		(105,000	)		—			—
	Net loss attributable to common stockholders	$	(171,807	)	$	(89,717	)	$	(92,359	)
	Weighted-average shares used to compute net loss per share, basic and diluted		37,877			3,670			3,543
	Basic and diluted net loss per share attributable to common stockholders	$	(4.54	)	$	(24.45	)	$	(26.07	)
Common Shares Outstanding were Excluded from Computation of Diluted Net Loss Per Share	'
	The following potential common shares outstanding were excluded from the computation of diluted net loss per share because including them would have been anti-dilutive (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Employee equity incentive plans		7,760			4,847			5,547
	Warrants to purchase convertible preferred stock		—			386			386
	Warrants to purchase common stock		—			50			50
	Convertible preferred stock		—			22,366			22,366
	Total common stock equivalents		7,760			27,649			28,349

Financial_Instruments_Tables

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Cash, Cash Equivalents and Short-Term Investments	'
	Cash, cash equivalents, and short-term investments consisted of the following as of December 31, 2013 (in thousands):
		Amortized			Unrealized			Unrealized			Estimated
		Cost			Gains			Losses			Fair Value
	Current assets:
	Cash	$	52,346		$	—		$	—		$	52,346
	Cash equivalents:
	Money market mutual funds		30,250			—			—			30,250
	Total cash equivalents		30,250			—			—			30,250
	Short-term fixed income securities:
	U.S. government and agency obligations		41,991			84			(21	)		42,054
	U.S. and foreign corporate debt securities		18,366			76			(1	)		18,441
	Foreign governments and multi-national agency obligations		2,764			—			(3	)		2,761
	Total short-term investments		63,121			160			(25	)		63,256
	Total cash, cash equivalents and short-term investments	$	145,717		$	160		$	(25	)	$	145,852
Contractual Maturities of Cash Equivalents and Short-Term Investments	'
	The contractual maturities of cash equivalents and short-term investments held at December 31, 2013 consisted of the following (in thousands):
		Amortized			Aggregate
		Cost Basis			Fair Value
	Due within one year	$	44,477		$	44,474
	Due after 1 year through 3 years		48,894			49,032
	Total cash equivalents & short-term investments	$	93,371		$	93,506
Schedule of Gross Unrealized Losses and Fair Values of Investments	'
	The following table presents gross unrealized losses and fair values for those investments that were in an unrealized loss position as of December 31, 2013, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in thousands):
		As of December 31, 2013
		Total (Less Than 12 Months)
		Fair Value			Unrealized Loss
	U.S. and foreign corporate debt securities	$	4,247		$	(1	)
	Foreign governments and multi-national agency obligations		2,761			(3	)
	U.S. government and agency obligations		12,566			(21	)
	Total	$	19,574		$	(25	)
Fair Value of Financial Assets Recorded on Recurring Basis	'
	As of December 31, 2013, financial assets recorded at fair value on a recurring basis were determined using the following inputs (in thousands):
		Fair Value Measurement Using
		Quoted Prices in			Significant Other			Significant			Total
		Active Markets			Observable			Unobservable
		for Identical			Inputs			Inputs
		Instruments			(Level 2)			(Level 3)
		(Level 1)
	Cash equivalents:
	Money-market funds	$	30,250		$	—		$	—		$	30,250
	Total cash equivalents		30,250			—			—			30,250
	Short-term investments:
	U.S. Government and agency obligations		—			42,054			—			42,054
	U.S. and foreign corporate debt securities		—			18,441			—			18,441
	Foreign governments and multi-national agency obligations		—			2,761			—			2,761
	Total short-term investments		—			63,256			—			63,256
	Total assets measured at fair value	$	30,250		$	63,256		$	—		$	93,506
Fair Value of Financial Liabilities Recorded on Recurring Basis	'
	As of December 31, 2012, financial liabilities recorded at fair value on a recurring basis were determined using the following inputs (in thousands):
		Fair Value Measurement Using
		Quoted Prices in			Significant Other			Significant			Total
		Active Markets			Observable			Unobservable
		for Identical			Inputs			Inputs
		Instruments			(Level 2)			(Level 3)
		(Level 1)
	Liabilities:
	Preferred stock warrants	$	—		$	—		$	11,261		$	11,261
	Embedded derivative		—			—			3,519			3,519
	Total liabilities measured at fair value	$	—		$	—		$	14,780		$	14,780
Carrying Amount and Estimated Fair Value of Convertible Promissory Notes and Compound Embedded Derivatives	'
	As of December 31, 2012, the carrying amount and estimated fair value of the convertible promissory notes and compound embedded derivatives using Level 3 measurements were as follows (in thousands):
		Carrying			Estimated
		Amount			Fair Value
	Convertible promissory notes	$	52,800		$	54,846
	Compound embedded derivatives		3,519			3,519
Summary of Roll-Forward of Fair Value of Convertible Preferred Stock Warrants and Compound Embedded Derivatives	'
	The following table provides a roll-forward of the fair value of the convertible preferred stock warrants and compound embedded derivatives valued with Level 3 inputs (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Beginning of period	$	14,780		$	15,018		$	17,035
	Issuance of convertible preferred stock warrants		—			—			9
	Remeasurement and termination of convertible preferred stock warrants		(11,261	)		(2,267	)		(3,516	)
	Issuance of compound embedded derivatives		—			3,640			1,490
	Remeasurement and extinguishment of compound embedded derivatives		(3,519	)		(1,611	)		—
	End of period	$	—		$	14,780		$	15,018

Balance_Sheet_Details_Tables

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'
Schedule of Deferred Revenue	'
	The following table details the activity in deferred revenue (in thousands):
		Year Ended December 31,
		2013			2012
	Deferred revenue, beginning of period	$	508,056		$	400,460
	Revenue deferred in the period		343,455			304,333
	Revenue recognized in the period		(326,858	)		(196,737	)
	Deferred revenue, end of period	$	524,653		$	508,056
Schedule of Deferred Cost of Revenue	'
	The following table details the activity in deferred cost of revenue (in thousands):
		Year Ended December 31,
		2013			2012
	Deferred cost of revenue, beginning of period	$	245,163		$	206,303
	Costs deferred related to revenue deferred in the period		170,213			147,229
	Cost of revenue recognized in the period		(139,253	)		(108,369	)
	Deferred cost of revenue, end of period	$	276,123		$	245,163
Components of Inventory	'
	Inventory consisted of the following (in thousands):
		December 31,
		2013			2012
	Component parts	$	141		$	299
	Finished goods		4,209			7,432
	Inventory	$	4,350		$	7,731
Schedule of Property and Equipment	'
	Property and equipment, net, consisted of the following (in thousands):
		December 31,
		2013			2012
	Computer and network equipment	$	15,328		$	13,356
	Software		13,003			10,970
	Machinery and equipment		8,543			7,807
	Furniture and fixtures		929			713
	Leasehold improvements		1,161			1,033
	Total property and equipment		38,964			33,879
	Less: Accumulated depreciation and amortization		(26,600	)		(21,178	)
	Property and equipment, net	$	12,364		$	12,701
Schedule of Other Long-Term Assets	'
	Other long-term assets consisted of the following (in thousands):
		December 31,
		2013			2012
	Goodwill and acquired intangible assets, net	$	671		$	864
	Prepaid expenses and deposits, non-current		896			10,390
	Other long-term assets	$	1,567		$	11,254
Schedule of Accrued Liabilities	'
	Accrued liabilities consisted of the following (in thousands):
		December 31,
		2013			2012
	Accrued payroll and related expenses	$	10,677		$	5,131
	Accrued operating expenses		3,949			3,488
	Product warranty, current		2,985			3,109
	Sales, property and income taxes		1,202			594
	Other		2,469			2,509
	Accrued liabilities	$	21,282		$	14,831
Schedule of Accumulated Other Comprehensive Income Loss	'
	The components of AOCI, net of tax, were as follows (in thousands):
		Foreign Currency			Unrealized Gains			Total
		Translation			on Available for
		Adjustments			Sale Securities
	Balance as of December 31, 2012	$	(136	)	$	—		$	(136	)
	Other comprehensive income (loss) before reclassification		182			84			266
	Amounts reclassified from AOCI		—			—			—
	Other comprehensive income		182			84			266
	Balance as of December 31, 2013	$	46		$	84		$	130

Borrowings_Tables

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Carrying Value of Convertible Notes and Compound Embedded Derivatives	'
	The following table provides a roll-forward of the carrying value of the convertible notes and compound embedded derivatives (in thousands):
		Convertible			Compound			Total
		Promissory			Embedded
		Notes			Derivatives
	Balances at December 31, 2012	$	52,800		$	3,519		$	56,319
	Accrued interest on convertible promissory notes		558			—			558
	Accretion of discount on convertible promissory notes		377			—			377
	Conversion of convertible promissory notes and embedded derivatives		(53,735	)		(3,519	)		(57,254	)
	Balances at December 31, 2013	$	—		$	—		$	—

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Schedule of Product Warranty Obligation	'
	Product warranty obligation is presented as follows on the consolidated balance sheets (in thousands):
		December 31,
		2013				2012
	Warranty obligation—classified in accrued liabilities	$	2,985			$	3,109
	Warranty obligation—classified in other liabilities		3,104				3,207
		$	6,089			$	6,316
Schedule of Product Warranty Activity	'
	Product warranty activity was as follows (in thousands):
		Year Ended
		December 31,
		2013				2012
	Warranty obligation—beginning of period	$	6,316			$	9,631
	Warranty expense for new warranties issued		1,406				1,372
	Utilization of warranty obligation		(1,767	)			(2,671	)
	Changes in estimates for pre-existing warranties		134				(2,016	)
	Warranty obligation—end of period	$	6,089			$	6,316
Summary of Sale Leaseback Transactions	'
	The following table provides a summary of the sale leaseback transactions that were outstanding as of December 31, 2013 (dollars in thousands):
	Lease Commencement	Lease Termination		Term				Interest		Financed
				(months)				rate		Amount
	Mar-12	March 2015			36				7.4		716
	Jun-12	Jun-15			36				6.7		960
										$	1,676
Future Minimum Commitments under Operating and Capital Leases	'
	As of December 31, 2013, the future minimum commitments under our operating and capital leases were as follows (in thousands):
		Operating				Capital
		Leases				Leases
	2014	$	5,088			$	1,752
	2015		5,145				1,162
	2016		3,928				112
	2017		179				—
	2018		183				—
	2019 and thereafter		1,075				—
	Net minimum lease payments	$	15,598				3,026
	Less amount representing interest						(188	)
	Present value of net minimum capital lease payments					$	2,838

Convertible_Preferred_Stock_an1

Convertible Preferred Stock and Preferred Stock Warrants (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Summary of Convertible Preferred Stock Converted into Common Stock	'
	Upon the closing of our IPO, all shares of our then-outstanding convertible preferred stock, as shown on the table below, automatically converted into shares of our common stock (see Note 1 Description of Business and Summary of Significant Accounting Policies, Initial Public Offering):
			Shares		Conversion			Shares			Conversion		Carrying		Aggregate
			Authorized		Price			Issued and			Ratio		Value		Liquidation
					Per Share			Outstanding			Per Share**				Preference
	Series A			4,800	$	4.7625			3,996			1	$	18,976	$	19,030
	Series A-1			420		4.7625			420			1		1,989		2,000
	Series B			6,085		1.8715			4,378			1		7,879		8,193
	Series C			7,933		7.5			6,849			1		49,176		51,365
	Series D			4,728		38.927			4,624			2.2899		89,643		180,000
	Series E			2,106		50			2,100			2.9412		103,062		120,750
				26,072					22,366	*			$	270,725	$	381,338
	*	Shares issued and outstanding does not total due to rounding.
	**	Based on our IPO price of $17.00 per share
Summary of Convertible Preferred Stock Warrants	'
	The following convertible preferred stock warrants were outstanding and fully vested as of December 31, 2012 and through the date prior to of our initial public offering (in thousands except per share data):
	Warrants to Purchase Convertible Preferred Stock		Price		Shares			Fair Value
			per Share
	Series A		$	4.7625		47		$	1,630
	Series C		$	7.5		333			9,627
	Series E		$	50		5			4
	Total					386	*	$	11,261
	*	Shares exercisable under outstanding warrants do not total due to rounding.

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Summary of Assumptions Used in Valuing Common Stock Warrant	'
	The following assumptions were used in valuing the common stock warrant:
	Expected volatility		49	%
	Expected dividends		0	%
	Expected term in years		5
	Risk-free interest rate		2.2	%
	Fair value of common stock	$	50.25

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation Expense	'
	We recorded stock-based compensation expense as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Cost of revenue	$	12,275		$	2,553		$	3,089
	Research and development		17,333			4,229			3,349
	Sales and marketing		7,060			2,822			2,425
	General and administrative		15,836			5,488			5,957
	Stock-based compensation expense	$	52,504		$	15,092		$	14,820
Summary of Stock Option Activity	'
	The following table summarizes our stock option activity and related information for the year ended December 31, 2013 (in thousands, except per share data):
		Options Outstanding
		Number of			Weighted			Weighted			Aggregate
		Shares			Average			Average			Intrinsic
					Exercise			Remaining			Value
					Price per			Contractual
					Share			Term (years)
	Balance at December 31, 2012		4,616		$	21.73
	Options granted		1,168			18.36
	Options exercised		(631	)		4.74
	Options cancelled or expired		(427	)		27.52
	Balance at December 31, 2013		4,726		$	11.88			6.43		$	43,146
	As of December 31, 2013:
	Options vested and expected to vest		4,651		$	11.76			6.38		$	42,988
	Options exercisable		3,382		$	9.39			5.41		$	39,267
Summary of Restricted Stock Unit Activity	'
	The following table summarizes our restricted stock unit activity and related information for the year ended December 31, 2013 (in thousands, except per share data):
		Restricted Stock
		Units Outstanding
		Number of			Weighted
		Shares			Average Grant
					Date Fair Value
					per Share
	Balance at December 31, 2012		231		$	49.51
	Restricted stock units granted		3,662			18.41
	Restricted stock units vested		(1,019	)		23.36
	Restricted stock units cancelled		(115	)		19.69
	Balance at December 31, 2013		2,759		$	19.14
Summary of Assumptions Relating to Stock Options	'
	The following table summarizes the assumptions relating to our stock options:
		Year Ended December 31,
		2013			2012			2011
	Expected volatility		47% – 52	%		53	%		48% – 54	%
	Expected dividends		0	%		0	%		0	%
	Expected life in years		5.00 – 6.08			5.95 – 6.08			5.50 – 6.08
	Risk-free interest rate		0.87% – 1.96	%		1	%		1.4% – 2.7	%
	Weighted average grant date fair value per share	$	19.11		$	21.2		$	24.7
Summary of Assumptions Relating to Employee Stock Purchase Plan	'
	The following table summarizes the assumptions relating to our ESPP:
	Expected volatility		52	%
	Expected dividends		0	%
	Expected life in years		< 1 year
	Risk-free interest rate		0.87	%

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Components of Loss Before Income Taxes	'
	The components of loss before income taxes are as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	United States	$	(28,774	)	$	(73,662	)	$	(83,050	)
	Foreign		(37,809	)		(15,665	)		(8,946	)
	Loss before income taxes	$	(66,583	)	$	(89,327	)	$	(91,996	)
Schedule of Provision (Benefit) for Income Taxes	'
	The provision (benefit) for income taxes consists of the following (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Current:
	United States federal	$	—		$	—		$	—
	State		(115	)		382			229
	Foreign		452			306			299
	Total current provision for income taxes		337			688			528
	Deferred:
	United States federal		(47	)		—			—
	State		123			—			(127	)
	Foreign		(189	)		(298	)		(38	)
	Total deferred provision (benefit) for income taxes		(113	)		(298	)		(165	)
	Provision for income taxes	$	224		$	390		$	363
Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate	'
	The provision for income taxes differs from the amount computed by applying the federal statutory income tax rate of 35% to loss before income taxes as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Federal statutory tax expense (benefit)	$	(23,304	)	$	(31,265	)	$	(32,199	)
	Research tax credit		(884	)		—			(486	)
	Effect of non-U.S. operations		13,320			5,469			3,321
	Change in valuation allowance		(925	)		23,732			27,843
	Stock-based compensation expense		3,455			2,665			2,718
	Remeasurement of preferred stock warrant liability		—			(752	)		(1,203	)
	Loss on debt extinguishments		8,287			—			—
	Other		275			541			369
	Provision for income taxes	$	224		$	390		$	363
Schedule of Components of Deferred Tax Assets and Liabilities	'
	The components of our deferred tax assets and liabilities are as follows (in thousands):
		December 31,
		2013			2012
	Deferred tax assets:
	Net operating loss and tax credit carryforwards	$	157,971		$	149,408
	Deferred revenue		96,054			100,380
	Stock-based compensation expense		11,415			6,202
	Warrant liability		0			32
	Accruals and reserves		5,793			4,849
	Intangible assets		1,480			1,532
	Other		343			65
	Gross deferred tax assets		273,056			262,468
	Valuation allowance		(168,092	)		(166,995	)
	Deferred tax assets		104,964			95,473
	Deferred tax liabilities
	Property and equipment, net		(1,905	)		(2,640	)
	Deferred cost of revenue		(102,459	)		(92,300	)
	Deferred tax liabilities		(104,364	)		(94,940	)
	Net deferred tax assets	$	600		$	533
Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits	'
	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands):
		Year Ended December 31,
		2013			2012			2011
	Unrecognized tax benefits—beginning of period	$	5,586		$	4,393		$	3,395
	Gross increase for tax positions of prior years		1,216			774			—
	Gross increase for tax positions of current year		1,913			419			998
	Unrecognized tax benefits balance—end of period	$	8,715		$	5,586		$	4,393

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Schedule of Revenue by Geographic Region	'
	The following table presents revenue by geographic region (in thousands):
		Year Ended December 31,
		2013		2012		2011
	Revenue:
	United States	$	285,430	$	181,948	$	225,564
	Australia		40,939		13,905		5,664
	All Other		489		884		5,822
	Total	$	326,858	$	196,737	$	237,050

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Statements of Operations Data	'
	The following tables set forth selected unaudited quarterly statements of operations data for each of the last eight quarters in the years ended December 31, 2013 and 2012 (in thousands, except per share data).
		Three Months Ended
		December 31,			September 30,			June 30,			March 31,			December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013			2012			2012			2012			2012
	Revenue, net	$	97,164		$	72,481		$	103,510		$	53,703		$	50,071		$	39,628		$	51,584		$	55,454
	Cost of revenue		63,420			49,255			55,260			43,569			39,523			35,194			44,914			45,387
	Gross profit		33,744			23,226			48,250			10,134			10,548			4,434			6,670			10,067
	Operating expenses		33,792			35,341			38,268			49,708			30,735			28,901			28,961			31,766
	Operating income (loss)		(48	)		(12,115	)		9,982			(39,574	)		(20,187	)		(24,467	)		(22,291	)		(21,699	)
	Other income (expense), net		138			(54	)		(184	)		(24,728	)		(902	)		(2,028	)		(1,078	)		3,325
	Income (loss) before income taxes		90			(12,169	)		9,798			(64,302	)		(21,089	)		(26,495	)		(23,369	)		(18,374	)
	Provision for income taxes		(268	)		100			328			64			(79	)		373			38			58
	Net income (loss)		358			(12,269	)		9,470			(64,366	)		(21,010	)		(26,868	)		(23,407	)		(18,432	)
	Deemed dividend to convertible preferred stockholders		—			—			—			(105,000	)		—			—			—			—
	Net income (loss) attributable to common stockholders	$	358		$	(12,269	)	$	9,470		$	(169,366	)	$	(21,010	)	$	(26,868	)	$	(23,407	)	$	(18,432	)
	Net income (loss) per share attributable to common stockholders:
	Basic	$	0.01		$	(0.26	)	$	0.2		$	(16.18	)	$	(5.65	)	$	(7.30	)	$	(6.38	)	$	(5.06	)
	Diluted	$	0.01		$	(0.26	)	$	0.19		$	(16.18	)	$	(5.65	)	$	(7.30	)	$	(6.38	)	$	(5.06	)
	Weighted average shares used to compute net income (loss) per share attributable to common stockholders:
	Basic		47,198			46,729			46,599			10,469			3,720			3,682			3,669			3,641
	Diluted		49,603			46,729			48,995			10,469			3,720			3,682			3,669			3,641

Description_of_Business_and_Su3

Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

2010 corporate bonus incentive plan and 2011 corporate bonus incentive plan [Member]

2011 corporate bonus incentive plan and 2012 corporate bonus incentive plan [Member]

Convertible promissory notes [Member]

Convertible promissory notes [Member]

Convertible promissory notes [Member]

Initial public offering [Member]

Initial public offering [Member]

Private placement [Member]

Reverse stock split [Member]

Stock options [Member]

Restricted stock units [Member]

Restricted stock units [Member]

Restricted stock units [Member]

Minimum [Member]

Maximum [Member]

December 2011 Note [Member]

February 2012 Note [Member]

2010 corporate bonus incentive plan and 2011 corporate bonus incentive plan [Member]

2011 corporate bonus incentive plan and 2012 corporate bonus incentive plan [Member]

Description Of Business And Summary Of Significant Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding capital stock

'

'

'

'

'

'

'

'

'

'

'

'5-for-1 reverse stock split

'

'

'

'

'

'

Reverse stock split effective date

'

'

'

'

'

'

'

'

'

'

'

11-Feb-13

'

'

'

'

'

'

Common stock shares issued

47,384,000

3,764,000

'

87,507

602,274

'

'

'

'

5,462,500

705,881

'

'

'

'

'

'

'

Price per share issued under IPO

$17

'

'

'

'

'

'

'

'

$17

$17

'

'

'

'

'

'

'

Proceeds from IPO

$84,247,000

'

'

'

'

'

'

'

$84,200,000

'

'

'

'

'

'

'

'

'

Underwriting discounts and commissions

'

'

'

'

'

'

'

'

6,500,000

'

'

'

'

'

'

'

'

'

Payment of offering costs during the period

'

'

'

'

'

'

'

'

2,200,000

'

'

'

'

'

'

'

'

'

Offering expenses

'

'

'

'

'

'

'

'

4,200,000

'

'

'

'

'

'

'

'

'

Proceeds from private placement

12,000,000

'

'

'

'

'

'

'

'

'

12,000,000

'

'

'

'

'

'

'

Outstanding convertible securities converted into common stock

32,406,995

'

'

'

'

3,764,954

'

'

'

'

'

'

'

'

'

'

'

'

Convertible notes, principal amount

'

'

'

'

'

'

24,000,000

30,000,000

'

'

'

'

'

'

'

'

'

'

Accrued interest on convertible notes

'

'

'

'

'

2,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Loss on debt extinguishments

22,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reduction in preferred stock warranty liability

11,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss due to termination of Series A and all Series C preferred stock warrants

800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payment for termination of warrants

12,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation expense

52,504,000

15,092,000

14,820,000

4,400,000

10,200,000

'

'

'

'

'

'

'

4,700,000

'

'

'

'

'

Restricted stock units vested in period

'

'

'

'

'

'

'

'

'

'

'

'

'

1,019,000

87,507,000

602,274,000

'

'

Deferred issuance costs

6,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred service costs of revenue

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Standard warranty period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'5 years

Extended product warranty period

'15 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Allowance for doubtful accounts

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Advertising costs

2,200,000

2,500,000

2,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-lived assets impairment charges

0

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred issuance cost, non - current

0

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments for termination of preferred stock warrants

12,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss due to reduction of preferred stock warrant liability

$800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Description_of_Business_and_Su4

Description of Business and Summary of Significant Accounting Policies - Schedule of Percentage of Revenue Related to Customers' Deployments in Excess of Ten Percent of Total Revenue (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pacific Gas and Electric Company [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Percentage of revenue	39.00%	30.00%	34.00%
FPL [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Percentage of revenue	20.00%	31.00%	26.00%
Oklahoma Gas and Electric Company [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Percentage of revenue	'	18.00%	'
SMUD [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Percentage of revenue	'	'	12.00%

Description_of_Business_and_Su5

Description of Business and Summary of Significant Accounting Policies - Schedule of Percentage of Accounts Receivable from Customers and Third Party Device Manufacturers in Excess of Ten Percent of Accounts Receivable (Detail) (Credit Concentration Risk [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Baltimore Gas and Electric Company [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	26.00%	26.00%
Landis + Gyr AG (acquired by Toshiba Corporation) [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	11.00%	'
Commonwealth Edison Company [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	10.00%	'
Virginia Electric and Power Company [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	10.00%	'
Secure Meters [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	'	16.00%
Progress Energy [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	'	15.00%
General Electric Company [Member]	'	'
Concentration Risk [Line Items]	'	'
Percentage of accounts receivable in excess of 10% accounts receivable	'	10.00%

Description_of_Business_and_Su6

Description of Business and Summary of Significant Accounting Policies - Property and Equipment Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2013
Leasehold improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives, description	'Lesser of the lease term or the estimated useful lives of the improvements, generally 1 to 4 years
Minimum [Member] | Software [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'3 years
Minimum [Member] | Computer and network equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'2 years
Minimum [Member] | Machinery and equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'3 years
Minimum [Member] | Furniture and fixtures [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'5 years
Minimum [Member] | Leasehold improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'1 year
Maximum [Member] | Software [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'7 years
Maximum [Member] | Computer and network equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'5 years
Maximum [Member] | Machinery and equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'5 years
Maximum [Member] | Furniture and fixtures [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'7 years
Maximum [Member] | Leasehold improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Property and equipment estimated useful lives	'4 years

Net_Loss_Per_Share_Additional_

Net Loss Per Share - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'	'
Deemed dividend to convertible preferred shareholders	$105,000	$105,000	'	'

Net_Loss_Per_Share_Computation

Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net loss	$358	($12,269)	$9,470	($64,366)	($21,010)	($26,868)	($23,407)	($18,432)	($66,807)	($89,717)	($92,359)
Deemed dividend to convertible preferred shareholders	'	'	'	-105,000	'	'	'	'	-105,000	'	'
Net loss attributable to common stockholders	$358	($12,269)	$9,470	($169,366)	($21,010)	($26,868)	($23,407)	($18,432)	($171,807)	($89,717)	($92,359)
Weighted-average shares used to compute net loss per share, basic and diluted	'	'	'	'	'	'	'	'	37,877	3,670	3,543
Basic and diluted net loss per share attributable to common stockholders	'	'	'	'	'	'	'	'	($4.54)	($24.45)	($26.07)

Net_Loss_Per_Share_Common_Shar

Net Loss Per Share - Common Shares Outstanding were Excluded from Computation of Diluted Net Loss Per Share (Detail)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Total common stock equivalents	7,760	27,649	28,349
Employee equity incentive plans [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Total common stock equivalents	7,760	4,847	5,547
Warrants to purchase convertible preferred stock [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Total common stock equivalents	'	386	386
Warrants to purchase common stock [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Total common stock equivalents	'	50	50
Convertible preferred stock [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Total common stock equivalents	'	22,366	22,366

Financial_Instruments_Cash_Cas

Financial Instruments - Cash, Cash Equivalents and Short-Term Investments (Detail) (Fair value on a recurring basis [Member], USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	$145,717
Unrealized Gains	160
Unrealized Losses	-25
Estimated Fair Value	145,852
U.S. Government and agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	41,991
Unrealized Gains	84
Unrealized Losses	-21
Estimated Fair Value	42,054
U.S. and foreign corporate debt securities [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	18,366
Unrealized Gains	76
Unrealized Losses	-1
Estimated Fair Value	18,441
Foreign governments and multi-national agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	2,764
Unrealized Gains	'
Unrealized Losses	-3
Estimated Fair Value	2,761
Short-term investments [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	63,121
Unrealized Gains	160
Unrealized Losses	-25
Estimated Fair Value	63,256
Cash [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	52,346
Unrealized Gains	'
Unrealized Losses	'
Estimated Fair Value	52,346
Cash equivalents [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	30,250
Unrealized Gains	'
Unrealized Losses	'
Estimated Fair Value	30,250
Cash equivalents [Member] | Money market mutual funds [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Amortized Cost	30,250
Unrealized Gains	'
Unrealized Losses	'
Estimated Fair Value	$30,250

Financial_Instruments_Addition

Financial Instruments - Additional Information (Detail) (USD $)

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 06, 2011

Dec. 06, 2011

Feb. 21, 2012

Dec. 31, 2012

Dec. 31, 2012

Feb. 21, 2012

Preferred stock warrants [Member]

Preferred stock warrants [Member]

Financial institution one [Member]

Financial institution one [Member]

Financial institution two [Member]

Financial institution two [Member]

Financial Institution Three [Member]

December 2011 Note [Member]

December 2011 Note [Member]

February 2012 Note [Member]

Convertible promissory notes [Member]

Convertible promissory notes [Member]

Convertible promissory notes [Member]

Monte Carlo simulation model [Member]

Monte Carlo simulation model [Member]

December 2011 Note [Member]

February 2012 Note [Member]

February 2012 Note [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash equivalents or short-term investments

'

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of cash and cash equivalents held in financial institutions

'

'

'

'

'

41.00%

50.00%

34.00%

44.00%

21.00%

'

'

'

'

'

'

Financial liabilities recorded at fair value on recurring basis

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Financial assets recorded at fair value on recurring basis

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible promissory note

'

'

'

'

'

'

'

'

'

'

'

'

'

24,000,000

30,000,000

'

Fair value of convertible notes

'

'

'

'

'

'

'

'

'

'

24,000,000

'

'

'

'

30,000,000

Fair values of compound embedded derivatives

'

3,519,000

'

'

'

'

'

'

'

'

'

1,500,000

3,600,000

1,800,000

1,700,000

'

Remeasurement and termination of convertible preferred stock warrants

($11,261,000)

($2,267,000)

($3,516,000)

$2,300,000

$3,500,000

'

'

'

'

'

'

'

'

'

'

'

Financial_Instruments_Contract

Financial Instruments - Contractual Maturities of Cash Equivalents and Short-Term Investments (Detail) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Disclosures [Abstract]	'
Due within one year, Amortized Cost Basis	$44,477
Due after 1 year through 3 years, Amortized Cost Basis	48,894
Total cash equivalents & short-term investments, Amortized Cost Basis	93,371
Due within one year, Aggregate Fair Value	44,474
Due after 1 year through 3 years, Aggregate Fair Value	49,032
Total cash equivalents & short-term investments, Aggregate Fair Value	$93,506

Financial_Instruments_Schedule

Financial Instruments - Schedule of Gross Unrealized Losses and Fair Values of Investments (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value Total (Less Than 12 Months)	$19,574
Unrealized Loss Total (Less Than 12 Months)	-25
U.S. and foreign corporate debt securities [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value Total (Less Than 12 Months)	4,247
Unrealized Loss Total (Less Than 12 Months)	-1
Foreign governments and multi-national agency obligations [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value Total (Less Than 12 Months)	2,761
Unrealized Loss Total (Less Than 12 Months)	-3
U.S. Government and agency obligations [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value Total (Less Than 12 Months)	12,566
Unrealized Loss Total (Less Than 12 Months)	($21)

Financial_Instruments_Fair_Val

Financial Instruments - Fair Value of Financial Assets Recorded on Recurring Basis (Detail) (Fair value on a recurring basis [Member], USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	$93,506
Cash equivalents [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	30,250
Cash equivalents [Member] | Money market mutual funds [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	30,250
Short-term investments [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	63,256
Short-term investments [Member] | U.S. Government and agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	42,054
Short-term investments [Member] | U.S. and foreign corporate debt securities [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	18,441
Short-term investments [Member] | Foreign governments and multi-national agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	2,761
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	30,250
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Cash equivalents [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	30,250
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Cash equivalents [Member] | Money market mutual funds [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	30,250
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Short-term investments [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Short-term investments [Member] | U.S. Government and agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Short-term investments [Member] | U.S. and foreign corporate debt securities [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Short-term investments [Member] | Foreign governments and multi-national agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Other Observable Inputs (Level 2) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	63,256
Significant Other Observable Inputs (Level 2) [Member] | Cash equivalents [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Other Observable Inputs (Level 2) [Member] | Cash equivalents [Member] | Money market mutual funds [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Other Observable Inputs (Level 2) [Member] | Short-term investments [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	63,256
Significant Other Observable Inputs (Level 2) [Member] | Short-term investments [Member] | U.S. Government and agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	42,054
Significant Other Observable Inputs (Level 2) [Member] | Short-term investments [Member] | U.S. and foreign corporate debt securities [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	18,441
Significant Other Observable Inputs (Level 2) [Member] | Short-term investments [Member] | Foreign governments and multi-national agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	2,761
Significant Unobservable Inputs (Level 3) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Cash equivalents [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Cash equivalents [Member] | Money market mutual funds [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Short-term investments [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Short-term investments [Member] | U.S. Government and agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Short-term investments [Member] | U.S. and foreign corporate debt securities [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'
Significant Unobservable Inputs (Level 3) [Member] | Short-term investments [Member] | Foreign governments and multi-national agency obligations [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Fair value of financial assets	'

Financial_Instruments_Fair_Val1

Financial Instruments - Fair Value of Financial Liabilities Recorded on Recurring Basis (Detail) (USD $)	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Preferred stock warrants	$11,261
Embedded derivative	3,519
Total liabilities measured at fair value	14,780
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Preferred stock warrants	'
Embedded derivative	'
Total liabilities measured at fair value	'
Significant Other Observable Inputs (Level 2) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Preferred stock warrants	'
Embedded derivative	'
Total liabilities measured at fair value	'
Significant Unobservable Inputs (Level 3) [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Preferred stock warrants	11,261
Embedded derivative	3,519
Total liabilities measured at fair value	$14,780

Financial_Instruments_Carrying

Financial Instruments - Carrying Amount and Estimated Fair Value of Convertible Promissory Notes and Compound Embedded Derivatives (Detail) (USD $)	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Compound embedded derivatives	$3,519
Carrying Amount [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Convertible promissory notes	52,800
Compound embedded derivatives	3,519
Estimated Fair Value [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Convertible promissory notes	54,846
Compound embedded derivatives	$3,519

Financial_Instruments_Summary_

Financial Instruments - Summary of Roll-Forward of Fair Value of Convertible Preferred Stock Warrants and Compound Embedded Derivatives (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value Disclosures [Abstract]	'	'	'
Beginning of period	$14,780	$15,018	$17,035
Issuance of convertible preferred stock warrants	'	'	9
Remeasurement and termination of convertible preferred stock warrants	-11,261	-2,267	-3,516
Issuance of compound embedded derivatives	'	3,640	1,490
Remeasurement and extinguishment of compound embedded derivatives	-3,519	-1,611	'
End of period	'	$14,780	$15,018

Balance_Sheet_Details_Schedule

Balance Sheet Details - Schedule of Deferred Revenue (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Revenue Disclosure [Abstract]	'	'
Deferred revenue, beginning of period	$508,056	$400,460
Revenue deferred in the period	343,455	304,333
Revenue recognized in the period	-326,858	-196,737
Deferred revenue, end of period	$524,653	$508,056

Balance_Sheet_Details_Schedule1

Balance Sheet Details - Schedule of Deferred Cost of Revenue (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Revenue Disclosure [Abstract]	'	'
Deferred cost of revenue, beginning of period	$245,163	$206,303
Costs deferred related to revenue deferred in the period	170,213	147,229
Cost of revenue recognized in the period	-139,253	-108,369
Deferred cost of revenue, end of period	$276,123	$245,163

Balance_Sheet_Details_Componen

Balance Sheet Details - Components of Inventory (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Component parts	$141	$299
Finished goods	4,209	7,432
Inventory	$4,350	$7,731

Balance_Sheet_Details_Addition

Balance Sheet Details - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance Sheet Details [Line Items]	'	'	'
Finished goods	$4,209,000	$7,432,000	'
Amortization expenses for intangible assets	192,000	192,000	289,000
Future amortization expense, year one	192,000	'	'
Future amortization expense, year two	33,000	'	'
Goodwill	447,000	447,000	'
Developed technology [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Gross carrying value of intangible assets	962,000	962,000	'
Accumulated amortization on intangible assets	738,000	545,000	'
Customer relationships [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Gross carrying value of intangible assets	260,000	260,000	'
Accumulated amortization on intangible assets	260,000	260,000	'
Assets held under capital leases [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Depreciation and amortization expense	6,500,000	7,100,000	6,700,000
Machinery and equipment [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Assets held under capital leases	6,300,000	5,300,000	'
Accumulated amortization for assets held under capital leases	3,800,000	2,200,000	'
Software [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Assets held under capital leases	3,500,000	3,000,000	'
Accumulated amortization for assets held under capital leases	2,200,000	1,600,000	'
Consigned inventory [Member]	'	'	'
Balance Sheet Details [Line Items]	'	'	'
Finished goods	$2,800,000	$3,500,000	'

Balance_Sheet_Details_Schedule2

Balance Sheet Details - Schedule of Property and Equipment (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	$38,964	$33,879
Less: Accumulated depreciation and amortization	-26,600	-21,178
Property and equipment, net	12,364	12,701
Computer and network equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	15,328	13,356
Software [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	13,003	10,970
Machinery and equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	8,543	7,807
Furniture and fixtures [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	929	713
Leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	$1,161	$1,033

Balance_Sheet_Details_Schedule3

Balance Sheet Details - Schedule of Other Long-Term Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]	'	'
Goodwill and acquired intangible assets, net	$671	$864
Prepaid expenses and deposits, non-current	896	10,390
Other long-term assets	$1,567	$11,254

Balance_Sheet_Details_Schedule4

Balance Sheet Details - Schedule of Accrued Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]	'	'
Accrued payroll and related expenses	$10,677	$5,131
Accrued operating expenses	3,949	3,488
Product warranty, current	2,985	3,109
Sales, property and income taxes	1,202	594
Other	2,469	2,509
Accrued liabilities	$21,282	$14,831

Balance_Sheet_Details_Schedule5

Balance Sheet Details - Schedule of Accumulated Other Comprehensive Income Loss (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance as of December 31, 2012	($136)	'	'
Other comprehensive income (loss) before reclassification	266	'	'
Amounts reclassified from AOCI	'	'	'
Other comprehensive income (loss)	266	-119	-65
Balance as of December 31, 2013	130	-136	'
Foreign Currency Translation Adjustments [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance as of December 31, 2012	-136	'	'
Other comprehensive income (loss) before reclassification	182	'	'
Amounts reclassified from AOCI	'	'	'
Other comprehensive income (loss)	182	'	'
Balance as of December 31, 2013	46	'	'
Unrealized Gains on Available for Sale Securities [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance as of December 31, 2012	'	'	'
Other comprehensive income (loss) before reclassification	84	'	'
Amounts reclassified from AOCI	'	'	'
Other comprehensive income (loss)	84	'	'
Balance as of December 31, 2013	$84	'	'

Borrowings_Additional_Informat

Borrowings - Additional Information (Detail) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

8-May-13

Apr. 30, 2013

Dec. 31, 2012

Mar. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Feb. 28, 2012

Dec. 31, 2011

Feb. 28, 2012

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2013

Feb. 28, 2012

Dec. 31, 2011

Initial public offering [Member]

December 2011 Note [Member]

February 2012 Note [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Subordinated convertible notes [Member]

Convertible preferred stock [Member]

Convertible preferred stock [Member]

Series E convertible preferred stock [Member]

Initial public offering [Member]

Initial public offering [Member]

Initial public offering [Member]

Convertible common stock [Member]

Convertible common stock [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility maximum borrowing capacity

'

$50,000,000

$40,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding letters of credit

9,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional letters of credit

40,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit agreement termination, date

17-May-15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, face amount

'

'

'

'

'

'

'

30,000,000

24,000,000

'

'

'

'

'

'

Maturity date

'

'

'

'

'

'

'

21-Feb-15

6-Dec-14

'

'

'

'

'

'

Description of debt instrument interest

'

'

'

'

'

'

'

'Interest accrued for the first six months at a rate of 3.0% per year and increased by 1.0% every six months to a maximum of 6.0% per year.

'Interest accrued for the first six months at a rate of 3.0% per year and increased by 1.0% every six months to a maximum of 6.0% per year.

'

'

'

'

'

'

Percentage of accrued interest, minimum

'

'

'

'

'

'

'

3.00%

3.00%

'

'

'

'

'

'

Percentage of increase in accrued interest

'

'

'

'

'

'

'

1.00%

1.00%

'

'

'

'

'

'

Percentage of accrued interest, maximum

'

'

'

'

'

'

'

6.00%

6.00%

'

'

'

'

'

'

Percentage of convertible stock

'

'

'

'

'

'

'

'

'

88.00%

85.00%

'

88.00%

88.00%

88.00%

Convertible Series E preferred stock per share

'

'

'

'

'

'

'

'

'

'

'

$50

'

'

'

Percentage of prepayment penalty

'

'

'

'

'

'

'

7.00%

7.00%

'

'

'

'

'

'

Written notice required to repay the convertible note

'

'

'

'

'

'

'

'10 days

'10 days

'

'

'

'

'

'

Fair value of note including compound embedded derivative at issuance

'

'

'

'

'

'

'

30,000,000

24,000,000

'

'

'

'

'

'

Fair value of compound embedded derivative

'

'

'

3,519,000

'

'

'

3,600,000

1,500,000

'

'

'

'

'

'

Accrued interest on convertible notes

'

'

'

'

'

'

'

'

'

'

'

'

2,300,000

'

'

Outstanding convertible securities converted into common stock

32,406,995

'

'

'

'

'

'

'

'

'

'

'

3,764,954

'

'

Price per share issued under IPO

$17

'

'

'

$17

'

'

'

'

'

'

'

$17

'

'

Loss on debt extinguishments

22,900,000

'

'

'

'

'

'

'

'

'

'

'

22,900,000

'

'

Debt instrument effective interest rate

'

'

'

'

'

6.89%

10.16%

'

'

'

'

'

'

'

'

Debt instrument outstanding amount

'

'

'

$55,800,000

'

'

'

'

'

'

'

'

'

'

'

Borrowings_Carrying_Value_of_C

Borrowings - Carrying Value of Convertible Notes and Compound Embedded Derivatives (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Debt Instrument [Line Items]	'
Beginning Balance	$56,319
Accrued interest on convertible promissory notes	558
Accretion of discount on convertible promissory notes	377
Conversion of convertible promissory notes and embedded derivatives	-57,254
Ending Balance	'
Convertible promissory notes [Member]	'
Debt Instrument [Line Items]	'
Beginning Balance	52,800
Accrued interest on convertible promissory notes	558
Accretion of discount on convertible promissory notes	377
Conversion of convertible promissory notes and embedded derivatives	-53,735
Ending Balance	'
Compound Embedded Derivatives [Member]	'
Debt Instrument [Line Items]	'
Beginning Balance	3,519
Accrued interest on convertible promissory notes	'
Accretion of discount on convertible promissory notes	'
Conversion of convertible promissory notes and embedded derivatives	-3,519
Ending Balance	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Schedule of Product Warranty Obligation (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Guarantor Obligations [Line Items]	'	'	'
Warranty obligation	$6,089	$6,316	$9,631
Accrued liabilities [Member]	'	'	'
Guarantor Obligations [Line Items]	'	'	'
Warranty obligation	2,985	3,109	'
Other liabilities [Member]	'	'	'
Guarantor Obligations [Line Items]	'	'	'
Warranty obligation	$3,104	$3,207	'

Commitments_and_Contingencies_2

Commitments and Contingencies - Schedule of Product Warranty Activity (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]	'	'
Warranty obligation-beginning of period	$6,316	$9,631
Warranty expense for new warranties issued	1,406	1,372
Utilization of warranty obligation	-1,767	-2,671
Changes in estimates for pre-existing warranties	134	-2,016
Warranty obligation-end of period	$6,089	$6,316

Commitments_and_Contingencies_3

Commitments and Contingencies - Additional Information (Detail)

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

8-May-13

Apr. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Standby letters of credit [Member]

Standby letters of credit [Member]

Standby letters of credit [Member]

Standby letters of credit [Member]

Standby letters of credit [Member]

Standby letters of credit [Member]

Minimum [Member]

Product [Member]

Product [Member]

Plaintiff

USD ($)

USD ($)

Australian dollars [Member]

Australian dollars [Member]

Australian dollars [Member]

Australian dollars [Member]

USD ($)

USD ($)

Claim

USD ($)

AUD

USD ($)

AUD

Recorded Unconditional Purchase Obligation [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase (reduction) of product warranty liability and product cost of revenue

$134,000

($2,016,000)

'

'

'

'

'

'

'

'

'

'

$100,000

($2,000,000)

Extended warranty, other current liabilities

206,000

362,000

'

'

'

'

'

'

'

'

'

'

'

'

Extended warranty, other long-term liabilities

7,100,000

5,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Rent expense facility leases

4,900,000

4,000,000

3,500,000

'

'

'

'

'

'

'

'

'

'

'

Lease term

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

Number of plaintiffs amended complaint

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of claims filed by plaintiffs

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit facility with financial institution

'

'

'

50,000,000

40,000,000

9,800,000

16,500,000

600,000

600,000

5,900,000

5,100,000

'

'

'

Unsecured surety bond

$15,000,000

$0

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_4

Commitments and Contingencies - Summary of Sale Leaseback Transactions (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Sale Leaseback Transaction [Line Items]	'
Financed Amount	$1,676
Lease Commencement, March 2012 [Member]	'
Sale Leaseback Transaction [Line Items]	'
Lease Commencement	'2012-03
Lease Termination	'2015-03
Term (months)	'36 months
Interest rate	7.40%
Financed Amount	716
Lease Commencement, June 2012 [Member]	'
Sale Leaseback Transaction [Line Items]	'
Lease Commencement	'2012-06
Lease Termination	'2015-06
Term (months)	'36 months
Interest rate	6.70%
Financed Amount	$960

Commitments_and_Contingencies_5

Commitments and Contingencies - Future Minimum Commitments under Operating and Capital Leases (Detail) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]	'
Operating leases, 2014	$5,088
Operating leases, 2015	5,145
Operating leases, 2016	3,928
Operating leases, 2017	179
Operating leases, 2018	183
Operating leases, 2019 and thereafter	1,075
Net minimum operating lease payments	15,598
Capital leases, 2014	1,752
Capital leases, 2015	1,162
Capital leases, 2016	112
Capital leases, 2017	'
Capital leases, 2018	'
Capital leases, 2019 and thereafter	'
Net minimum capital lease payments	3,026
Less amount representing interest	-188
Present value of net minimum capital lease payments	$2,838

Convertible_Preferred_Stock_an2

Convertible Preferred Stock and Preferred Stock Warrants - Summary of Convertible Preferred Stock Converted into Common Stock (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Per Share data, unless otherwise specified
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	10,000	0
Convertible Preferred Stock, Carrying Value	'	$270,725
Convertible Preferred Stock Series A [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	4,800	'
Convertible Preferred Stock, Conversion Price Per Share	4.7625	'
Convertible Preferred Stock, Shares Issued and Outstanding	3,996	'
Convertible Preferred Stock, Conversion Ratio Per Share	1	'
Convertible Preferred Stock, Carrying Value	18,976	'
Convertible Preferred Stock, Aggregate Liquidation Preference	19,030	'
Convertible Preferred Stock Series A-1 [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	420	'
Convertible Preferred Stock, Conversion Price Per Share	4.7625	'
Convertible Preferred Stock, Shares Issued and Outstanding	420	'
Convertible Preferred Stock, Conversion Ratio Per Share	1	'
Convertible Preferred Stock, Carrying Value	1,989	'
Convertible Preferred Stock, Aggregate Liquidation Preference	2,000	'
Convertible Preferred Stock Series B [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	6,085	'
Convertible Preferred Stock, Conversion Price Per Share	1.8715	'
Convertible Preferred Stock, Shares Issued and Outstanding	4,378	'
Convertible Preferred Stock, Conversion Ratio Per Share	1	'
Convertible Preferred Stock, Carrying Value	7,879	'
Convertible Preferred Stock, Aggregate Liquidation Preference	8,193	'
Convertible Preferred Stock Series C [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	7,933	'
Convertible Preferred Stock, Conversion Price Per Share	7.5	'
Convertible Preferred Stock, Shares Issued and Outstanding	6,849	'
Convertible Preferred Stock, Conversion Ratio Per Share	1	'
Convertible Preferred Stock, Carrying Value	49,176	'
Convertible Preferred Stock, Aggregate Liquidation Preference	51,365	'
Convertible Preferred Stock Series D [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	4,728	'
Convertible Preferred Stock, Conversion Price Per Share	38.927	'
Convertible Preferred Stock, Shares Issued and Outstanding	4,624	'
Convertible Preferred Stock, Conversion Ratio Per Share	2.2899	'
Convertible Preferred Stock, Carrying Value	89,643	'
Convertible Preferred Stock, Aggregate Liquidation Preference	180,000	'
Convertible Preferred Stock Series E [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	2,106	'
Convertible Preferred Stock, Conversion Price Per Share	50	'
Convertible Preferred Stock, Shares Issued and Outstanding	2,100	'
Convertible Preferred Stock, Conversion Ratio Per Share	2.9412	'
Convertible Preferred Stock, Carrying Value	103,062	'
Convertible Preferred Stock, Aggregate Liquidation Preference	120,750	'
Convertible preferred stock [Member]	'	'
Temporary Equity [Line Items]	'	'
Convertible preferred stock, shares authorized	26,072	'
Convertible Preferred Stock, Shares Issued and Outstanding	22,366	'
Convertible Preferred Stock, Carrying Value	270,725	'
Convertible Preferred Stock, Aggregate Liquidation Preference	381,338	'

Convertible_Preferred_Stock_an3

Convertible Preferred Stock and Preferred Stock Warrants - Summary of Convertible Preferred Stock Converted into Common Stock (Parenthetical) (Detail) (USD $)	Dec. 31, 2013
Equity [Abstract]	'
Price per share under IPO	$17

Convertible_Preferred_Stock_an4

Convertible Preferred Stock and Preferred Stock Warrants - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended	0 Months Ended		12 Months Ended
	Dec. 31, 2013	Mar. 11, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Mar. 11, 2013	Mar. 11, 2013	Dec. 31, 2013
				Series D preferred stock [Member]	Series E convertible preferred stock [Member]	Series A Preferred Stock [Member]	Series C Preferred Stock [Member]	Private placement [Member]
Subsidiary, Sale of Stock [Line Items]	'	'	'	'	'	'	'	'
Outstanding convertible securities converted into common stock	32,406,995	'	'	'	'	'	'	'
Conversion price for preferred stockholders, per share	'	'	'	$38.93	$50	'	'	'
Deemed dividend	'	'	'	'	$105,000,000	'	'	'
Affiliates ownership on common stock	'	32.70%	'	'	'	'	'	'
Warrants held to purchase preferred stock shares	'	'	'	'	'	41,993	333,333	'
Payments for termination of preferred stock warrants	12,000,000	'	'	'	'	'	'	'
Reduction in preferred stock warrant liability	11,200,000	'	'	'	'	'	'	'
Loss due to reduction of preferred stock warrant liability	800,000	'	'	'	'	'	'	'
Proceeds from private placement	$12,000,000	'	'	'	'	'	'	$12,000,000
Common stock shares issued	47,384,000	'	3,764,000	'	'	'	'	705,881
Price per share issued under private placement	$17	'	'	'	'	'	'	$17
Preferred stock converted in to warrants to purchase common stock	20,768	'	'	'	'	'	'	'

Convertible_Preferred_Stock_an5

Convertible Preferred Stock and Preferred Stock Warrants - Summary of Convertible Preferred Stock Warrants (Detail) (USD $)	Dec. 31, 2012
In Thousands, unless otherwise specified
Temporary Equity [Line Items]	'
Warrants to Purchase convertible Preferred Stock, Shares	386
Warrants to Purchase Convertible Preferred Stock, Fair value	$11,261
Warrants to Purchase Series A Convertible Preferred Stock [Member]	'
Temporary Equity [Line Items]	'
Warrants to Purchase Convertible Preferred Stock, Price per Share	4.7625
Warrants to Purchase convertible Preferred Stock, Shares	47
Warrants to Purchase Convertible Preferred Stock, Fair value	1,630
Warrants to Purchase Series C Convertible Preferred Stock [Member]	'
Temporary Equity [Line Items]	'
Warrants to Purchase Convertible Preferred Stock, Price per Share	7.5
Warrants to Purchase convertible Preferred Stock, Shares	333
Warrants to Purchase Convertible Preferred Stock, Fair value	9,627
Warrants to Purchase Series E Convertible Preferred Stock [Member]	'
Temporary Equity [Line Items]	'
Warrants to Purchase Convertible Preferred Stock, Price per Share	50
Warrants to Purchase convertible Preferred Stock, Shares	5
Warrants to Purchase Convertible Preferred Stock, Fair value	$4

Common_Stock_Additional_Inform

Common Stock - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]	'	'
Convertible preferred stock, shares authorized	10,000,000	0
2012 Equity Incentive Plan [Member]	'	'
Class of Stock [Line Items]	'	'
Common stock shares reserved for issuance	3,400,000	'
ESPP [Member]	'	'
Class of Stock [Line Items]	'	'
Common stock shares reserved for issuance	400,000	'
Maximum employees contribution	15.00%	'
Purchase price of common stock	'The purchase price of the stock is the lower of 85% of the fair market value on (a) the first day of the offering period or (b) the purchase date.	'
Purchase price of the stock as a percent of price of common stock	85.00%	'
Stock options [Member] | 2012 Equity Incentive Plan [Member]	'	'
Class of Stock [Line Items]	'	'
Common stock shares reserved for issuance	2,500,000	3,000,000
Terms of options granted	'ISO options granted to a person who, at the time of the grant, owns more than 10% of the voting power of all classes of stock must be at no less than 110% of the fair market value and expire five years from the date of grant. All other options generally have a contractual term of 10 years.	'
Vesting period	'4 years	'
Minimum [Member] | Restricted stock units [Member] | 2012 Equity Incentive Plan [Member]	'	'
Class of Stock [Line Items]	'	'
Vesting period	'2 years	'
Maximum [Member] | Restricted stock units [Member] | 2012 Equity Incentive Plan [Member]	'	'
Class of Stock [Line Items]	'	'
Vesting period	'4 years	'
Restated certificate of incorporation [Member]	'	'
Class of Stock [Line Items]	'	'
Increased number of authorized shares of common stock	1,000,000,000	'
Voting power description	'Provided that at least two-thirds of the voting power of all of the then-outstanding shares of our capital stock is required to amend the bylaws	'
Undesignated preferred stock [Member] | Restated certificate of incorporation [Member]	'	'
Class of Stock [Line Items]	'	'
Convertible preferred stock, shares authorized	10,000,000	'

Common_Stock_Additional_Inform1

Common Stock - Additional Information (Common Stock Warrants) (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Class of Warrant or Right [Line Items]	'	'	'
Purchase of common stock by granted warrant	50,000	'	'
Exercise price of common stock warrant	$0.01	'	'
Warrant expires on exercisable and non-forfeitable	31-Mar-16	'	'
Fair value of the warrant	$2.50	'	'
Preferred stock converted in to warrants to purchase common stock	'	20,768	'
Common stock issued	'	47,384,000	3,764,000
Warrant [Member]	'	'	'
Class of Warrant or Right [Line Items]	'	'	'
Preferred stock converted in to warrants to purchase common stock	'	20,768	'
Weighted average exercise price	'	13.91	'
Common stock issued	'	57,370	'

Common_Stock_Summary_of_Assump

Common Stock - Summary of Assumptions Used in Valuing Common Stock Warrant (Detail) (Warrant [Member], USD $)	12 Months Ended
	Dec. 31, 2011
Warrant [Member]	'
Class of Stock [Line Items]	'
Expected volatility	49.00%
Expected dividends	0.00%
Expected term in years	'5 years
Risk-free interest rate	2.20%
Fair value of common stock	$50.25

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	$52,504	$15,092	$14,820
Cost of revenue [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	12,275	2,553	3,089
Research and development [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	17,333	4,229	3,349
Sales and marketing [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	7,060	2,822	2,425
General and administrative [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Stock-based compensation expense	$15,836	$5,488	$5,957

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Beginning balance	4,616
Number of Shares, Options granted	1,168
Number of Shares, Options exercised	-631
Number of Shares, Options cancelled or expired	-427
Ending balance	4,726
Number of Shares, Options vested and expected to vest	4,651
Number of Shares, Options exercisable	3,382
Weighted Average Exercise Price Per Share, Beginning balance	$21.73
Weighted Average Exercise Price Per Share, Options granted	$18.36
Weighted Average Exercise Price Per Share, Options exercised	$4.74
Weighted Average Exercise Price Per Share, Options cancelled or expired	$27.52
Weighted Average Exercise Price Per Share, Ending balance	$11.88
Weighted Average Exercise Price Per Share, Options vested and expected to vest	$11.76
Weighted Average Exercise Price Per Share, Options exercisable	$9.39
Weighted Average Remaining Contractual Term, Ending balance	'6 years 5 months 5 days
Weighted Average Remaining Contractual Term, Options vested and expected to vest	'6 years 4 months 17 days
Weighted Average Remaining Contractual Term, Options exercisable	'5 years 4 months 28 days
Aggregate Intrinsic Value, Ending balance	$43,146
Aggregate Intrinsic Value, Options vested and expected to vest	42,988
Aggregate Intrinsic Value, Option exercisable	$39,267

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
				2012 Equity Incentive Plan [Member]	2012 Equity Incentive Plan [Member]	Expected compensation expense [Member]
						2012 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Cash received from the exercise of stock options	$2.90	$0.60	$0.80	'	'	'
Intrinsic value of stock options exercised	9.5	6.6	5.7	'	'	'
Incremental stock-based compensation expense	4.7	'	'	'	'	1.3
Common stock shares purchased	'	'	'	1,752,895	'	'
Common stock exercise price per share	'	'	'	$34.90	'	'
Common stock price per share	'	'	'	$17	'	'
Weighted-average period of recognized stock-based compensation expenses	'2 years 2 months 12 days	'	'	'	'1 year 2 months 12 days	'
Unrecognized compensation cost related to non-vested stock-based compensation	52.3	'	'	'	'	'
Fair value of stock options and restricted stock units that vested	$19.50	$0.30	$0	'	'	'

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) (Restricted stock units [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013
Restricted stock units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning balance, Number of Shares	231
Restricted stock units granted, Number of Shares	3,662
Restricted stock units vested, Number of Shares	-1,019
Restricted stock units cancelled, Number of Shares	-115
Ending balance, Number of Shares	2,759
Beginning balance, Weighted Average Grant Date Fair Value per Share	$49.51
Restricted stock units granted, Weighted Average Grant Date Fair Value per Share	$18.41
Restricted stock units vested, Weighted Average Grant Date Fair Value per Share	$23.36
Restricted stock units cancelled, Weighted Average Grant Date Fair Value per Share	$19.69
Ending balance, Weighted Average Grant Date Fair Value per Share	$19.14

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Assumptions Relating to Stock Options (Detail) (Stock options [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected volatility	'	53.00%	'
Expected volatility, minimum	47.00%	'	48.00%
Expected volatility, maximum	52.00%	'	54.00%
Expected dividends	0.00%	0.00%	0.00%
Risk-free interest rate	'	1.00%	'
Risk-free interest rate, minimum	0.87%	'	1.40%
Risk-free interest rate, maximum	1.96%	'	2.70%
Weighted average grant date fair value per share	$19.11	$21.20	$24.70
Minimum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected life in years, maximum	'5 years	'5 years 11 months 12 days	'5 years 6 months
Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected life in years, maximum	'6 years 29 days	'6 years 29 days	'6 years 29 days

StockBased_Compensation_Summar3

Stock-Based Compensation - Summary of Assumptions Relating to Employee Stock Purchase Plan (Detail) (ESPP [Member])	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Expected volatility	52.00%
Expected dividends	0.00%
Risk-free interest rate	0.87%
Minimum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Expected life in years	'1 year

Income_Taxes_Schedule_of_Compo

Income Taxes - Schedule of Components of Loss Before Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
United States	($28,774)	($73,662)	($83,050)
Foreign	-37,809	-15,665	-8,946
Loss before income taxes	($66,583)	($89,327)	($91,996)

Income_Taxes_Schedule_of_Provi

Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:	'	'	'	'	'	'	'	'	'	'	'
United States federal	'	'	'	'	'	'	'	'	'	'	'
State	'	'	'	'	'	'	'	'	-115	382	229
Foreign	'	'	'	'	'	'	'	'	452	306	299
Total current provision for income taxes	'	'	'	'	'	'	'	'	337	688	528
Deferred:	'	'	'	'	'	'	'	'	'	'	'
United States federal	'	'	'	'	'	'	'	'	-47	'	'
State	'	'	'	'	'	'	'	'	123	'	-127
Foreign	'	'	'	'	'	'	'	'	-189	-298	-38
Total deferred provision (benefit) for income taxes	'	'	'	'	'	'	'	'	-113	-298	-165
Provision for income taxes	($268)	$100	$328	$64	($79)	$373	$38	$58	$224	$390	$363

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]	'	'	'
U.S. federal statutory tax rate	35.00%	'	'
Increase in valuation allowance	$1.10	$25.20	$30.50
Undistributed earnings of foreign subsidiaries	1.4	'	'
Unrecognized tax benefits netted against related deferred tax assets	7.1	4.5	'
Federal [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Net operating loss carryforwards	390.4	'	'
Net operating loss carryforwards, annual limitation	41.4	'	'
Net operating loss carryforwards, expiration date	'2027	'	'
Research tax credit carryforwards	8.2	'	'
Tax credit carryforwards, expiration date	'2024	'	'
State [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Net operating loss carryforwards	365.4	'	'
Net operating loss carryforwards, annual limitation	41.4	'	'
Net operating loss carryforwards, expiration date	'2016	'	'
Research tax credit carryforwards	9	'	'
Tax credit carryforwards, expiration date	'No expiration date	'	'
Federal [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Tax effect of undistributed earnings of foreign subsidiaries	$0	'	'

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Federal statutory tax expense (benefit)	'	'	'	'	'	'	'	'	($23,304)	($31,265)	($32,199)
Research tax credit	'	'	'	'	'	'	'	'	-884	'	-486
Effect of non-U.S. operations	'	'	'	'	'	'	'	'	13,320	5,469	3,321
Change in valuation allowance	'	'	'	'	'	'	'	'	-925	23,732	27,843
Stock-based compensation expense	'	'	'	'	'	'	'	'	3,455	2,665	2,718
Remeasurement of preferred stock warrant liability	'	'	'	'	'	'	'	'	'	-752	-1,203
Loss on debt extinguishments	'	'	'	'	'	'	'	'	8,287	'	'
Other	'	'	'	'	'	'	'	'	275	541	369
Provision for income taxes	($268)	$100	$328	$64	($79)	$373	$38	$58	$224	$390	$363

Income_Taxes_Schedule_of_Compo1

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets:	'	'
Net operating loss and tax credit carryforwards	$157,971	$149,408
Deferred revenue	96,054	100,380
Stock-based compensation expense	11,415	6,202
Warrant liability	'	32
Accruals and reserves	5,793	4,849
Intangible assets	1,480	1,532
Other	343	65
Gross deferred tax assets	273,056	262,468
Valuation allowance	-168,092	-166,995
Deferred tax assets	104,964	95,473
Deferred tax liabilities	'	'
Property and equipment, net	-1,905	-2,640
Deferred cost of revenue	-102,459	-92,300
Deferred tax liabilities	-104,364	-94,940
Net deferred tax assets	$600	$533

Income_Taxes_Reconciliation_of1

Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Unrecognized tax benefits-beginning of period	$5,586	$4,393	$3,395
Gross increase for tax positions of prior years	1,216	774	'
Gross increase for tax positions of current year	1,913	419	998
Unrecognized tax benefits balance-end of period	$8,715	$5,586	$4,393

Segment_Information_Additional

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013
	Segment
Segment Reporting [Abstract]	'
Number of reportable segment	1

Segment_Information_Schedule_o

Segment Information - Schedule of Revenue by Geographic Region (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'	'	'	'	'	'	'	'	'
Total revenue, net	$97,164	$72,481	$103,510	$53,703	$50,071	$39,628	$51,584	$55,454	$326,858	$196,737	$237,050
Operating Segments [Member] | United States [Member]	'	'	'	'	'	'	'	'	'	'	'
Revenue:	'	'	'	'	'	'	'	'	'	'	'
Total revenue, net	'	'	'	'	'	'	'	'	285,430	181,948	225,564
Operating Segments [Member] | Australia [Member]	'	'	'	'	'	'	'	'	'	'	'
Revenue:	'	'	'	'	'	'	'	'	'	'	'
Total revenue, net	'	'	'	'	'	'	'	'	40,939	13,905	5,664
Operating Segments [Member] | All Other [Member]	'	'	'	'	'	'	'	'	'	'	'
Revenue:	'	'	'	'	'	'	'	'	'	'	'
Total revenue, net	'	'	'	'	'	'	'	'	$489	$884	$5,822

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data - Schedule of Quarterly Statements of Operations Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Revenue, net	$97,164	$72,481	$103,510	$53,703	$50,071	$39,628	$51,584	$55,454	$326,858	$196,737	$237,050
Cost of revenue	63,420	49,255	55,260	43,569	39,523	35,194	44,914	45,387	211,504	165,018	214,099
Gross profit	33,744	23,226	48,250	10,134	10,548	4,434	6,670	10,067	115,354	31,719	22,951
Operating expenses	33,792	35,341	38,268	49,708	30,735	28,901	28,961	31,766	157,109	120,363	118,181
Operating income (loss)	-48	-12,115	9,982	-39,574	-20,187	-24,467	-22,291	-21,699	-41,755	-88,644	-95,230
Other income (expense), net	138	-54	-184	-24,728	-902	-2,028	-1,078	3,325	-24,828	-683	3,234
Income (loss) before income taxes	90	-12,169	9,798	-64,302	-21,089	-26,495	-23,369	-18,374	-66,583	-89,327	-91,996
Provision for income taxes	-268	100	328	64	-79	373	38	58	224	390	363
Net income (loss)	358	-12,269	9,470	-64,366	-21,010	-26,868	-23,407	-18,432	-66,807	-89,717	-92,359
Deemed dividend to convertible preferred stockholders	'	'	'	-105,000	'	'	'	'	-105,000	'	'
Net income (loss) attributable to common stockholders	$358	($12,269)	$9,470	($169,366)	($21,010)	($26,868)	($23,407)	($18,432)	($171,807)	($89,717)	($92,359)
Net income (loss) per share attributable to common stockholders:	'	'	'	'	'	'	'	'	'	'	'
Basic	$0.01	($0.26)	$0.20	($16.18)	($5.65)	($7.30)	($6.38)	($5.06)	'	'	'
Diluted	$0.01	($0.26)	$0.19	($16.18)	($5.65)	($7.30)	($6.38)	($5.06)	'	'	'
Weighted average shares used to compute net income (loss) per share attributable to common stockholders:	'	'	'	'	'	'	'	'	'	'	'
Basic	47,198	46,729	46,599	10,469	3,720	3,682	3,669	3,641	'	'	'
Diluted	49,603	46,729	48,995	10,469	3,720	3,682	3,669	3,641	'	'	'