Castlight Health (CSLT) 10-Q 12 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Nov. 10, 2014	Nov. 10, 2014
		Class A [Member]	Class B [Member]
Class of Stock [Line Items]	'	'	'
Document Type	'10-Q	'	'
Amendment Flag	'false	'	'
Document Period End Date	30-Sep-14	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'Q3	'	'
Trading Symbol	'CSLT	'	'
Entity Registrant Name	'CASTLIGHT HEALTH, INC.	'	'
Entity Central Index Key	'0001433714	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Non-accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	59,586,244	30,705,200

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$25,231	$25,154
Marketable securities	156,931	42,017
Accounts receivable, net	11,278	5,065
Deferred commissions	3,399	3,648
Prepaid expenses and other current assets	3,344	1,583
Total current assets	200,183	77,467
Property and equipment, net	3,228	2,631
Marketable securities, noncurrent	27,700	0
Restricted cash, noncurrent	0	101
Deferred commissions, noncurrent	2,577	1,821
Other assets	292	1,497
Total assets	233,980	83,517
Current liabilities:	'	'
Accounts payable	2,708	2,536
Accrued expenses and other current liabilities	4,826	4,998
Accrued compensation	10,078	8,064
Deferred revenue	18,111	6,925
Total current liabilities	35,723	22,523
Deferred revenue, noncurrent	7,995	4,548
Other liabilities, noncurrent	290	373
Total liabilities	44,008	27,444
Commitments and contingencies	'	'
Stockholdersb equity (deficit):	'	'
Additional paid-in capital	387,443	6,885
Accumulated other comprehensive income	12	0
Accumulated deficit	-197,492	-131,236
Total stockholdersb equity (deficit)	189,972	-124,350
Total liabilities, convertible preferred stock and stockholdersb equity (deficit)	233,980	83,517
Convertible Preferred Stock [Member]	'	'
Liabilities, convertible preferred stock and stockholdersb equity (deficit)	'	'
Convertible preferred stock	0	180,423
Class A [Member]	'	'
Stockholdersb equity (deficit):	'	'
Common stock value issued	6	1
Class B [Member]	'	'
Stockholdersb equity (deficit):	'	'
Common stock value issued	$3	$0

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Revenue:	'		'		'		'
Subscription	$11,254		$3,213		$28,293		$7,040
Professional services	955		396		2,825		801
Total revenue	12,209		3,609		31,118		7,841
Cost of revenue:	'		'		'		'
Cost of subscription	2,596	[1]	1,510	[1]	8,223	[1]	4,174	[1]
Cost of professional services	4,559	[1]	3,325	[1]	12,932	[1]	7,751	[1]
Total cost of revenue	7,155		4,835		21,155		11,925
Gross profit (loss)	5,054		-1,226		9,963		-4,084
Operating expenses:	'		'		'		'
Sales and marketing	14,760	[1]	8,706	[1]	46,267	[1]	21,579	[1]
Research and development	5,630	[1]	4,138	[1]	16,633	[1]	10,662	[1]
General and administrative	4,944	[1]	2,571	[1]	13,473	[1]	6,012	[1]
Total operating expenses	25,334		15,415		76,373		38,253
Operating loss	-20,280		-16,641		-66,410		-42,337
Other income, net	81		38		154		128
Net loss	($20,199)		($16,603)		($66,256)		($42,209)
Net loss per share, basic and diluted	($0.23)		($1.63)		$0		$0
Weighted-average shares used to compute basic and diluted net loss per share	89,698		10,168		68,960		9,684
[1]	Includes stock-based compensation expense as follows: Cost of subscription $60 , $1, 99, 2. Cost of professional services $306, $33, 726,85. Sales and marketing $2,013 , $175., 4339,583. Research and development $561 , $98, 1,475 , 208. General and administrative $1,169 , $223

Consolidated_Statements_of_Ope1

Consolidated Statements of Operations Parenthetical (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Cost of subscription [Member]	'	'	'	'
Allocated Share-based Compensation Expense	$60	$1	$99	$2
Cost of professional services [Member]	'	'	'	'
Allocated Share-based Compensation Expense	306	33	726	85
Sales and marketing [Member]	'	'	'	'
Allocated Share-based Compensation Expense	2,013	175	4,339	583
Research and development [Member]	'	'	'	'
Allocated Share-based Compensation Expense	561	98	1,475	208
General and administrative [Member]	'	'	'	'
Allocated Share-based Compensation Expense	$1,169	$223	$2,963	$495

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Consolidated Statement of Comprehensive Loss:	'	'	'	'
Net loss	($20,199)	($16,603)	($66,256)	($42,209)
Other comprehensive income (loss):	'	'	'	'
Net change in unrealized gain (loss) on available-for-sale marketable securities	52	15	12	-20
Reclassification adjustments for net realized gains (loss) on available-for-sale marketable securities	0	0	0	0
Other comprehensive income (loss)	52	15	12	-20
Comprehensive loss	($20,147)	($16,588)	($66,244)	($42,229)

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating activities:	'	'
Net loss	($66,256)	($42,209)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation	944	401
Stock-based compensation	9,602	1,373
Amortization of deferred commissions	3,119	741
Accretion and amortization of marketable securities	1,021	585
Expense related to warrant	2,659	0
Changes in operating assets and liabilities:	'	'
Accounts receivable	-6,213	-1,348
Deferred commissions	-3,626	-3,301
Prepaid expenses and other assets	-1,922	-270
Accounts payable	193	228
Accrued expenses and other liabilities	2,753	2,947
Deferred revenue	14,633	5,332
Net cash used in operating activities	-43,093	-35,521
Investing activities:	'	'
Decrease Restricted cash	101	0
Purchase of property and equipment	-1,398	-2,279
Purchase of marketable securities	-210,388	-42,288
Sale of marketable securities	13,000	5,000
Maturities of marketable securities	53,765	58,835
Net cash (used in) provided by investing activities	-144,920	19,268
Financing activities:	'	'
Proceeds from the exercise of stock options	1,928	314
Net proceeds from initial public offering	186,162	0
Net cash provided by financing activities	188,090	314
Net increase (decrease) in cash and cash equivalents	77	-15,939
Cash and cash equivalents at beginning of period	25,154	42,534
Cash and cash equivalents at end of period	$25,231	$26,595

Organization_and_Description_o

Organization and Description of Business	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Description of Business	'
	Organization and Description of Business
	Description of Business
	Castlight Health, Inc. (Castlight) is a pioneer in a new category of cloud-based software that enables enterprises to gain control over their rapidly escalating healthcare costs. Our Enterprise Healthcare Cloud allows our customers to conquer the complexity of the existing healthcare system by providing personalized, actionable information to their employees, implementing technology-enabled benefit designs and integrating disparate systems and applications. Our comprehensive technology offering aggregates complex, large-scale data and applies sophisticated analytics to make health care cost and quality data transparent and useful. We were incorporated in the State of Delaware in January 2008 as Maria Health, Inc. In November 2008, we changed our name to Ventana Health Services, and in April 2010, we changed our name to Castlight, Inc., and then subsequently changed our name to Castlight Health, Inc. Our principal executive offices are located in San Francisco, California.
	Initial Public Offering
	On March 19, 2014, we completed our initial public offering (IPO), in which we sold 12.8 million shares of Class B common stock at a price to the public of $16.00 per share. The aggregate offering price for shares sold in the offering was approximately $204.2 million. We raised approximately $185.6 million in net proceeds from the offering, after deducting underwriter discounts and commissions of approximately $14.3 million and other offering expenses of approximately $4.3 million.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (GAAP), for interim financial information and with the instructions to Form 10-Q and Article 10 of Securities and Exchange Commission (SEC), Regulation S-X. In the opinion of management, the information herein reflects all adjustments, consisting only of normal recurring adjustments except as otherwise noted, considered necessary for a fair statement of results of operations, financial position and cash flows. The condensed consolidated financial statements include the results of Castlight and its wholly owned U.S. subsidiary. The results for the interim periods presented are not necessarily indicative of the results expected for any future period.
	The condensed consolidated balance sheet as of December 31, 2013 included herein was derived from the audited financial statements as of that date. The following information should be read in conjunction with the audited consolidated financial statements and notes included in Castlight’s prospectus dated March 13, 2014 and filed with the SEC on March 14, 2014 pursuant to Rule 424(b) under the Securities Act of 1933. There have been no changes to our significant accounting policies described in the prospectus that have had a material impact on our condensed consolidated financial statements and related notes.
	On December 30, 2013, our board of directors and stockholders authorized a one-for-one exchange of all outstanding Class B common stock to Class A common stock. All share, per share and related information presented in these financial statements and accompanying footnotes have been retroactively adjusted to reflect the impact of this exchange.
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires us to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. These estimates include, but are not limited to, the determination of the relative selling prices for our services and certain assumptions used in the valuation of our common stock prior to the IPO and in equity awards. Actual results could differ from those estimates, and such differences could be material to our consolidated financial position and results of operations.
	Segment Information
	Our chief operating decision maker, our CEO, reviews the financial information presented on a consolidated basis for purposes of allocating resources and evaluating our financial performance. Accordingly, we have determined that we operate in a single reporting segment, cloud applications.
	Revenue Recognition
	We derive our revenue from sales of cloud-based subscription service contracts, including support, and professional services contracts. We sell subscriptions to our cloud-based subscription service through contracts that are generally three years in length.
	Our cloud-based subscription service contracts do not provide customers with the right to take possession of the software supporting the cloud-based service and, as a result, are accounted for as service contracts.
	We commence revenue recognition for our cloud-based subscription service and professional services when all of the following criteria are met:
	•	there is persuasive evidence of an arrangement;
	•	the service has been provided to the customer;
	•	collection of the fees is reasonably assured; and
	•	the amount of fees to be paid by the customer is fixed or determinable.
	Our subscription and professional service arrangements do not contain refund provisions for fees earned related to services performed, with the exception of our commitments under service-level agreements, as discussed under "Warranties and Indemnification" below.
	Subscription Revenue.    Subscription revenue recognition commences on the date that our cloud-based service is made available to the customer, which is considered the launch date, provided all of the other criteria described above are met. Revenue is recognized based on the terms in our customer contracts, which can provide for (a) a variable periodic fee based upon the actual or contractual number of users that is recognized to revenue or (b) a fixed fee that is recognized to revenue on a straight-line basis over the contractual term of the arrangement.
	Certain of our cloud-based subscription arrangements include performance incentives that are generally based upon employee engagement. Fees for performance incentives are considered contingent revenue, and are recognized over the remaining term of the related subscription arrangement commencing at the time they are earned.
	Professional Services Revenue.    Professional services revenue is comprised of implementation services related to our cloud-based subscription service, as well as follow-on professional services to assist our customers in further adopting our cloud-based subscription service, and communications services. Nearly all of our professional services contracts are sold on a fixed-fee basis. We do not have standalone value for our implementation services. Accordingly, we recognize implementation services revenue in the same manner as the associated cloud-based subscription service, beginning on the launch date, provided all other criteria described above have been met. For follow-on professional services that are sold separately from the cloud-based subscription service, we recognize revenue as the services are delivered. Communication services revenue is recognized over the contractual term, generally one year, commencing when the revenue recognition criteria have been met.
	Multiple Deliverable Arrangements.    To date, we have generated substantially all our revenue from multiple deliverable arrangements consisting of multi-year cloud-based subscription services and professional services, including implementation services and communication services. For arrangements with multiple deliverables, we evaluate whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, we account for each deliverable separately and revenue is recognized for the respective deliverables as they are delivered. If one or more of the deliverables do not have standalone value upon delivery, the deliverables that do not have standalone value are generally combined with our cloud-based subscription service, and revenue for the combined unit is recognized over the remaining term of the cloud-based subscription service.
	Our deliverables have standalone value if we or any other vendor sells a similar service separately. We have concluded that we have standalone value for our cloud-based subscription service as we sell these services separately through renewals and for our communication services as other vendors sell similar services separately. Conversely, we have concluded that our implementation services do not have standalone value, as we and others do not yet sell these services separately. Accordingly, we consider the separate units of accounting in our multiple deliverable arrangements to be the communication services and a combined deliverable comprised of cloud-based subscription services and implementation services.
	When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangements accounting guidance provides a hierarchy to use when determining the relative selling price for each unit of accounting. Vendor-specific objective evidence, or VSOE, of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence, or TPE, of selling price is used to establish the selling price if it exists. If TPE does not exist, we estimate the best estimated selling price, or BESP. VSOE does not currently exist for any of our deliverables. Additionally, we do not believe TPE is a practical alternative due to differences in our cloud-based subscription service compared to other parties and the availability of relevant third-party pricing information for our cloud-based subscription service and our other services. Accordingly, for arrangements with multiple deliverables that can be separated into different units of accounting, we allocate the arrangement fee to the separate units of accounting based on our BESP. The amount of arrangement fee allocated is limited by contingent revenue, if any.
	We determine BESP for our deliverables by considering our overall pricing objectives and market conditions. This includes evaluating our pricing practices, our list prices, the size of our transactions, historical standalone sales and our go-to-market strategy. The determination of BESP is made through consultation with and approval by management. For financial statement presentation purposes, we allocate the fees from our combined units of accounting to subscription and professional services based upon their relative selling price.
	Costs of Revenue
	Cost of revenue consists of the cost of subscription revenue and cost of professional services revenue.
	Cost of subscription revenue primarily consists of data fees, employee-related expenses (including salaries, benefits and stock-based compensation) related to hosting costs of our cloud-based service, cost of subcontractors, expenses for service delivery (which includes call center support), allocated overhead, the costs of data center capacity and depreciation of owned computer equipment and software.
	Cost of professional services revenue consists primarily of employee-related expenses associated with these services, the cost of subcontractors and travel costs. The time and costs of our customer implementations vary based on the source and condition of the data we receive from third parties, the configurations that we agree to provide and the size of the customer.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of highly liquid investments with original maturities of three months or less from the date of purchase. Our cash and cash equivalents generally consist of investments in money market funds, U.S. treasury securities and U.S. government-issued obligations. Cash and cash equivalents are stated at fair value.
	Marketable Securities
	Our marketable securities consist of U.S. agency obligations, U.S. treasury securities and money market funds, with maturities at the time of purchase of greater than three months. Marketable securities with remaining maturities in excess of one year are classified as noncurrent. We classify our marketable securities as available-for-sale at the time of purchase based on our intent and are recorded at their estimated fair value. Unrealized gains and losses for available-for-sale securities are recorded in other comprehensive income (loss). We evaluate our investments to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses and declines in value judged to be other than temporary are determined based on the specific identification method and are reported in other income, net in the condensed consolidated statements of operations.
	Internal-use Software
	For our development costs related to our cloud-based service, we capitalize costs incurred during the application development stage. Costs related to preliminary project and post-implementation stages are expensed as incurred. Capitalized software development costs are included as part of property, plant and equipment and are amortized on a straight-line basis over the technology's estimated useful life, which is generally three years. The amortization expense is recorded as a component of cost of subscription revenue.
	During the three and nine months ended September 30, 2014, we capitalized software costs totaling $0.2 million. All software development costs incurred in prior periods have been expensed.
	Deferred Commissions
	Deferred commissions are the incremental costs that are directly associated with the noncancelable portion of cloud-based subscription service contracts with customers and consist of sales commissions paid to our direct sales force. The commissions are deferred and amortized over the noncancelable terms of the related contracts. The deferred commission amounts are recoverable through the future revenue streams under the noncancelable customer contracts. Amortization of deferred commissions is included in sales and marketing expense in the condensed consolidated statements of operations.
	Deferred Revenue
	Deferred revenue primarily consists of professional services and cloud-based subscription services that have been billed in advance of revenue being recognized or the services have not been delivered. Additionally, deferred revenue consists of professional services that have been billed and delivered but the revenue is being deferred and recognized together with a cloud-based subscription contract as a single unit of accounting. We invoice our customers for our cloud-based subscription services based on the terms of the contract, which can be annual, quarterly or monthly installments. We invoice our customers for our professional services and the first year of communication services generally at contract execution. Deferred revenue that is anticipated to be recognized during the succeeding 12-month period is recorded as current deferred revenue, and the remaining portion is recorded as noncurrent.
	Stock-based Compensation
	All stock-based compensation to employees is measured based on the grant-date fair value of the awards and recognized in our condensed consolidated statements of operations over the period during which the employee is required to perform services in exchange for the award (generally the vesting period of the award). We estimate the fair value of stock options granted using the Black-Scholes option valuation model. Compensation expense is recognized over the vesting period of the applicable award using the straight-line method.
	Compensation expense for non-employee stock options and warrants is calculated using the Black-Scholes option-pricing model and is recorded as the options vest. Options subject to vesting are required to be periodically revalued over their service period, which is generally the same as the vesting period.
	Warranties and Indemnification
	Our cloud-based service is generally warranted to be performed in a professional manner and in a manner that will comply with the terms of the customer agreements.
	Our arrangements generally include certain provisions for indemnifying customers against liabilities if there is a breach of a customer’s data or if our service infringes a third party’s intellectual property rights. To date, we have not incurred any material costs as a result of such indemnifications and have not accrued any liabilities related to such obligations in the financial statements. We have entered into service-level agreements with certain customers warranting defined levels of performance and response and permitting those customers to receive credits for prepaid amounts related to subscription services in the event that we fail to meet those levels. To date, we have not experienced any significant failures to meet defined levels of performance and response as a result of those agreements.
	We have also agreed to indemnify our directors and executive officers for costs associated with any fees, expenses, judgments, fines and settlement amounts incurred by any of these persons in any action or proceeding to which any of those persons is, or is threatened to be, made a party by reason of the person’s service as a director or officer, including any action by us, arising out of that person’s services as our director or officer or that person’s services provided to any other company or enterprise at our request. We maintain director and officer insurance coverage that would generally enable us to recover a portion of any future amounts paid. We may also be subject to indemnification obligation by law with respect to the actions of our employees under certain circumstances and in certain jurisdictions.
	Recently Issued and Adopted Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09 regarding ASC Topic 606, Revenue from Contracts with Customers. The standard provides principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance will be effective for us beginning January 1, 2017. Early adoption is not permitted. We are currently evaluating the accounting, transition and disclosure requirements of the standard and cannot currently estimate the financial statement impact of adoption.

Marketable_Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Marketable Securities	'
	Marketable Securities
	At September 30, 2014 and December 31, 2013, respectively, marketable securities consisted of the following (in thousands):
		Amortized		Unrealized		Unrealized			Fair Value
		Cost		Gains		Losses
	September 30, 2014
	U.S. agency obligations	$	182,406	$	20	$	(12	)	$	182,414
	U.S. treasury securities	5,635		4		—			5,639
	Money market mutual funds	11,692		—		—			11,692
		199,733		24		(12		)	199,745
	Included in cash and cash equivalents	15,114		—		—			15,114
	Included in marketable securities	$	156,920	$	20	$	(9	)	$	156,931
	Included in marketable securities, noncurrent	$	27,699	$	4	$	(3	)	$	27,700
		Amortized		Unrealized		Unrealized			Fair Value
		Cost		Gains		Losses
	December 31, 2013
	U.S. agency obligations	$	35,996	$	6	$	(7	)	$	35,995
	U.S. treasury securities	6,020		2		—			6,022
	Money market mutual funds	18,082		—		—			18,082
		60,098		8		(7		)	60,099
	Included in cash and cash equivalents	18,082		—		—			18,082
	Included in marketable securities	$	42,016	$	8	$	(7	)	$	42,017

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	We measure our financial assets and liabilities at fair value at each reporting period using a fair value hierarchy that requires that we maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s classification within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value:
	Level 1—Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.
	Level 2—Include other inputs that are directly or indirectly observable in the marketplace.
	Level 3—Unobservable inputs that are supported by little or no market activity.
	The fair value of marketable securities included in the Level 2 category is based on observable inputs, such as quoted prices for similar assets at the measurement date; quoted prices in markets that are not active; or other inputs that are observable, either directly or indirectly. These values were obtained from a third-party pricing service and were evaluated using pricing models that vary by asset class and may incorporate available trade, bid and other market information and price quotes from well-established third party pricing vendors and broker-dealers. There have been no changes in valuation techniques in the periods presented. We have no financial assets or liabilities measured using Level 3 inputs. There were no significant transfers between Levels 1 and 2 assets as of September 30, 2014 and December 31, 2013. The following tables present information about our assets that are measured at fair value on a recurring basis using the above input categories (in thousands):
		Level 1		Level 2		Total
	30-Sep-14
	Cash equivalents:
	Money market mutual funds	$	11,692	$	—	$	11,692
	Marketable securities:
	U.S. agency obligations	—		182,414		182,414
	U.S. treasury securities	—		5,639		5,639
		$	11,692	$	188,053	$	199,745
		Level 1		Level 2		Total
	December 31, 2013
	Cash equivalents:
	Money market mutual funds	$	18,082	$	—	$	18,082
	Marketable securities:
	U.S. agency obligations	—		35,995		35,995
	U.S. treasury securities	—		6,022		6,022
		$	18,082	$	42,017	$	60,099
	Gross unrealized gains and losses for cash equivalents and marketable securities as of September 30, 2014 and December 31, 2013 were not material. We do not believe the unrealized losses represent other-than-temporary impairments based on our evaluation of available evidence as of September 30, 2014.
	There were no realized gains or losses during the three and nine months ended September 30, 2014 and 2013. As of September 30, 2014 those securities with maturities at the time of purchase of greater than one year are reflected in the noncurrent portion of our condensed consolidated balance sheets. All of our marketable securities at December 31, 2013 mature within one year. Marketable securities on the balance sheets consist of securities with original or remaining maturities at the time of purchase of greater than three months, and the remainder of the securities is reflected in cash and cash equivalents.

Property_and_equipment_net

Property and equipment, net	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property and equipment	'
	Property and Equipment
	Property and equipment consisted of the following (in thousands):
		As of
		September 30, 2014			December 31, 2013
	Leasehold improvements	$	1,043		$	924
	Computer equipment	2,635			2,024
	Software	824			263
	Capitalization of internal-use software	162			—
	Furniture and equipment	301			257
	Total	4,965			3,468
	Accumulated depreciation	(1,737		)	(837		)
	Property and equipment, net	$	3,228		$	2,631
	Depreciation expense for the three months ended September 30, 2014 and 2013, was $0.3 million, and $0.2 million, respectively, and for the nine months ended September 30, 2014 and 2013, $0.9 million and $0.4 million, respectively. Depreciation is recorded on a straight-line basis.

Deferred_Revenue

Deferred Revenue	9 Months Ended
	Sep. 30, 2014
Deferred Revenue Disclosure [Abstract]	'
Deferred Revenue	'
	Deferred Revenue
	Deferred revenue consisted of the following (in thousands):
		As of
		September 30, 2014		December 31, 2013
	Subscription	$	12,387	$	3,810
	Professional services—implementation	2,891		1,835
	Professional services—communications	2,833		1,280
	Total current	18,111		6,925
	Subscription	3,379		1,489
	Professional services—implementation	4,209		2,443
	Professional services—communications	407		616
	Total noncurrent	7,995		4,548
	Total	$	26,106	$	11,473

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Leases and Contractual Obligations
	We lease office space under noncancelable operating leases in San Francisco, California. Contractual obligations relate to our service agreements for our data centers in Colorado and Arizona and other third party service providers.
	Legal Matters
	We may become subject to legal proceedings, claims and litigation arising in the ordinary course of business. In addition, we may receive letters alleging infringement of patents or other intellectual property rights. We are not a party to any material legal proceedings, nor are we aware of any pending or threatened litigation that would have a material adverse effect on our business, operating results, cash flows or financial condition should such litigation be resolved unfavorably.

Stockholders_Equity_Deficit

Stockholders' Equity (Deficit)	9 Months Ended
	Sep. 30, 2014
Equity and Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stockholders' Equity (Deficit)	'
	Stockholders’ Equity (Deficit)
	Initial Public Offering
	On March 19, 2014, we completed our IPO, in which we sold 12.8 million shares of Class B common stock at a price to the public of $16.00 per share. Upon the consummation of the IPO, all outstanding shares of convertible preferred stock were converted into shares of Class A common stock as follows:
			As of September 30, 2014				As of December 31, 2013
			Shares			Shares Issued and	Shares		Shares Issued and	Liquidation
			Authorized			Outstanding	Authorized		Outstanding	Preference
	Convertible Preferred Stock:
		Series A	—			—	8,000,000		8,000,000	$	1,000,000
		Series A-1	—			—	10,000,000		10,000,000	3,000,000
		Series B	—			—	15,315,314		15,315,314	17,000,000
		Series C	—			—	14,594,598		14,594,598	60,000,000
		Series D	—			—	16,565,750		16,565,721	100,000,000
		Total	—			—	64,475,662		64,475,633	181,000,000
	Stockholders' equity:
		Preferred stock	10,000,000			—	—		—	—
		Class A common stock	200,000,000			62,622,110	95,000,000		10,994,074	—
		Class B common stock	800,000,000			27,307,588	95,000,000		—	—
		Total	1,010,000,000			89,929,698	254,475,662		75,469,707	$	181,000,000
	Employee Equity Plans
	We adopted a 2014 Equity Incentive Plan (EIP) that became effective on March 12, 2014 and serves as the successor to our 2008 Stock Incentive Plan. We reserved 15.0 million shares of our Class B common stock for future issuance under various terms provided for in the EIP. Shares issued under the 2008 Stock Plan were Class A common stock and shares issued under the EIP are Class B common stock.
	We adopted a 2014 Employee Stock Purchase Plan (ESPP) that became effective on March 13, 2014 that enables eligible employees to purchase shares of our Class B common stock at a discount. We reserved 6.0 million shares of our Class B common stock for issuance under various terms provided for in the ESPP. We have not yet established a start date of the initial purchasing period under the ESPP.
	Stock Options Activity
	A summary of stock option activity for the nine months ended September 30, 2014 is as follows (in thousands, except share and per share amounts):
		Options			Weighted-		Aggregate
		Outstanding			Average		Intrinsic
					Exercise		Value
					Price
	Balance at December 31, 2013	16,455,404			$	1.22	$	91,192
	Stock option grants	4,132,429			$	12.51
	Stock options exercised	(1,693,338	)		$	1.14
	Stock options canceled	(1,664,236	)		$	3.38
	Balance at September 30, 2014	17,230,259			$	3.73	$	158,743
	The total grant-date fair value of stock options granted during the nine months ended September 30, 2014 and 2013 was $32.1 million and $4.1 million, respectively.
	Stock-Based Compensation to Employees
	The fair value of each option grant was estimated on the date of grant using the Black-Scholes option-valuation model with the following assumptions and fair value per share:
		Nine Months Ended September 30,
		2014		2013
	Volatility	60%		57.8%-60%
	Expected life (in years)	5.0-6.2		5.0-6.5
	Risk-free interest rate	1.53%-2.05%		0.7%-1.8%
	Dividend yield	—%		—%
	Weighted-average fair value of underlying common stock	$13.60		$1.44
	As of September 30, 2014, we had $26.5 million in unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over a weighted-average period of approximately 3.1 years.
	Warrants
	On December 11, 2013, we issued a warrant to purchase an aggregate of 175,000 shares of Class A common stock at an exercise price of $5.00 per share to a third-party service provider. The warrant provides for an early exercise right and has a 10 year term. As of September 30, 2014 seventy percent of the warrants were vested and the remaining thirty percent will vest on December 31, 2014. Expense for the warrants is calculated using the Black-Scholes-Merton option-pricing model and is recorded over the service performance period, which is the same as the vesting period. For the nine months ended September 30, 2014, we recorded $2.7 million in expense associated with this warrant. The expense for the three months ended September 30, 2014 was immaterial.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The effective tax rate for the three and nine months ended September 30, 2014 and 2013 was zero percent, primarily as a result of the estimated tax loss for the year and the change in valuation allowance.
	There were no material changes to the unrecognized tax benefits in the three and nine months ended September 30, 2014, and we do not anticipate that the unrecognized tax benefits will significantly increase or decrease in the next 12 months. At September 30, 2014, all unrecognized tax benefits are subject to a full valuation allowance and, if recognized, will not affect the effective tax rate.

Net_Loss_per_Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Net Loss per Share	'
	Net Loss per Share
	Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, less the weighted-average unvested common stock subject to repurchase. Diluted net loss per share is computed by giving effect to all potential shares of common stock, including Preferred Stock and outstanding stock options and warrants, to the extent dilutive. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential shares of common stock outstanding would have been anti-dilutive.
	When shares of both Class A and Class B common stock are outstanding, net loss is allocated based on the contractual participation rights of the Class A and Class B common stock as if the earnings for the year have been distributed. As the liquidation and dividend rights are identical, the net loss is allocated on a proportionate basis. As of September 30, 2013, only shares of Class A common stock were outstanding and therefore no net loss was allocated.
	The following table presents the calculation of basic and diluted net loss per share for our common stock (in thousands, except per share data):
		Three Months Ended September 30,										Nine Months Ended September 30,
		2014							2013			2014						2013
		Class A				Class B			Class A			Class A			Class B			Class A
	Net loss	$	(16,356	)		$	(3,843	)	$	(16,603	)	$	(55,833	)	$	(10,423	)	$	(42,209	)
	Weighted-average shares used to compute basic and diluted net loss per share	72,633				17,065			10,168			58,112			10,848			9,684
	Basic and diluted net loss per share	$	(0.23	)		$	(0.23	)	$	(1.63	)	$	(0.96	)	$	(0.96	)	$	(4.36	)
	The following securities were excluded from the calculation of diluted net loss per share for common stock because their effect would have been anti-dilutive for the periods presented (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014		2013
	Convertible preferred stock	—			64,476			—		64,476
	Stock options and restricted common stock	17,230			13,615			17,230		13,615
	Warrants	115			—			115		—
		17,345			78,091			17,345		78,091

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Accounting Presentation and Principles of Consolidation	'
	Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (GAAP), for interim financial information and with the instructions to Form 10-Q and Article 10 of Securities and Exchange Commission (SEC), Regulation S-X. In the opinion of management, the information herein reflects all adjustments, consisting only of normal recurring adjustments except as otherwise noted, considered necessary for a fair statement of results of operations, financial position and cash flows. The condensed consolidated financial statements include the results of Castlight and its wholly owned U.S. subsidiary. The results for the interim periods presented are not necessarily indicative of the results expected for any future period.
	The condensed consolidated balance sheet as of December 31, 2013 included herein was derived from the audited financial statements as of that date. The following information should be read in conjunction with the audited consolidated financial statements and notes included in Castlight’s prospectus dated March 13, 2014 and filed with the SEC on March 14, 2014 pursuant to Rule 424(b) under the Securities Act of 1933. There have been no changes to our significant accounting policies described in the prospectus that have had a material impact on our condensed consolidated financial statements and related notes.
Use of Estimates	'
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires us to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. These estimates include, but are not limited to, the determination of the relative selling prices for our services and certain assumptions used in the valuation of our common stock prior to the IPO and in equity awards. Actual results could differ from those estimates, and such differences could be material to our consolidated financial position and results of operations.
Segment Information	'
	Segment Information
	Our chief operating decision maker, our CEO, reviews the financial information presented on a consolidated basis for purposes of allocating resources and evaluating our financial performance. Accordingly, we have determined that we operate in a single reporting segment, cloud applications.
Revenue Recognition	'
	Revenue Recognition
	We derive our revenue from sales of cloud-based subscription service contracts, including support, and professional services contracts. We sell subscriptions to our cloud-based subscription service through contracts that are generally three years in length.
	Our cloud-based subscription service contracts do not provide customers with the right to take possession of the software supporting the cloud-based service and, as a result, are accounted for as service contracts.
	We commence revenue recognition for our cloud-based subscription service and professional services when all of the following criteria are met:
	•	there is persuasive evidence of an arrangement;
	•	the service has been provided to the customer;
	•	collection of the fees is reasonably assured; and
	•	the amount of fees to be paid by the customer is fixed or determinable.
	Our subscription and professional service arrangements do not contain refund provisions for fees earned related to services performed, with the exception of our commitments under service-level agreements, as discussed under "Warranties and Indemnification" below.
	Subscription Revenue.    Subscription revenue recognition commences on the date that our cloud-based service is made available to the customer, which is considered the launch date, provided all of the other criteria described above are met. Revenue is recognized based on the terms in our customer contracts, which can provide for (a) a variable periodic fee based upon the actual or contractual number of users that is recognized to revenue or (b) a fixed fee that is recognized to revenue on a straight-line basis over the contractual term of the arrangement.
	Certain of our cloud-based subscription arrangements include performance incentives that are generally based upon employee engagement. Fees for performance incentives are considered contingent revenue, and are recognized over the remaining term of the related subscription arrangement commencing at the time they are earned.
	Professional Services Revenue.    Professional services revenue is comprised of implementation services related to our cloud-based subscription service, as well as follow-on professional services to assist our customers in further adopting our cloud-based subscription service, and communications services. Nearly all of our professional services contracts are sold on a fixed-fee basis. We do not have standalone value for our implementation services. Accordingly, we recognize implementation services revenue in the same manner as the associated cloud-based subscription service, beginning on the launch date, provided all other criteria described above have been met. For follow-on professional services that are sold separately from the cloud-based subscription service, we recognize revenue as the services are delivered. Communication services revenue is recognized over the contractual term, generally one year, commencing when the revenue recognition criteria have been met.
	Multiple Deliverable Arrangements.    To date, we have generated substantially all our revenue from multiple deliverable arrangements consisting of multi-year cloud-based subscription services and professional services, including implementation services and communication services. For arrangements with multiple deliverables, we evaluate whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, we account for each deliverable separately and revenue is recognized for the respective deliverables as they are delivered. If one or more of the deliverables do not have standalone value upon delivery, the deliverables that do not have standalone value are generally combined with our cloud-based subscription service, and revenue for the combined unit is recognized over the remaining term of the cloud-based subscription service.
	Our deliverables have standalone value if we or any other vendor sells a similar service separately. We have concluded that we have standalone value for our cloud-based subscription service as we sell these services separately through renewals and for our communication services as other vendors sell similar services separately. Conversely, we have concluded that our implementation services do not have standalone value, as we and others do not yet sell these services separately. Accordingly, we consider the separate units of accounting in our multiple deliverable arrangements to be the communication services and a combined deliverable comprised of cloud-based subscription services and implementation services.
	When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangements accounting guidance provides a hierarchy to use when determining the relative selling price for each unit of accounting. Vendor-specific objective evidence, or VSOE, of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence, or TPE, of selling price is used to establish the selling price if it exists. If TPE does not exist, we estimate the best estimated selling price, or BESP. VSOE does not currently exist for any of our deliverables. Additionally, we do not believe TPE is a practical alternative due to differences in our cloud-based subscription service compared to other parties and the availability of relevant third-party pricing information for our cloud-based subscription service and our other services. Accordingly, for arrangements with multiple deliverables that can be separated into different units of accounting, we allocate the arrangement fee to the separate units of accounting based on our BESP. The amount of arrangement fee allocated is limited by contingent revenue, if any.
	We determine BESP for our deliverables by considering our overall pricing objectives and market conditions. This includes evaluating our pricing practices, our list prices, the size of our transactions, historical standalone sales and our go-to-market strategy. The determination of BESP is made through consultation with and approval by management. For financial statement presentation purposes, we allocate the fees from our combined units of accounting to subscription and professional services based upon their relative selling price.
Costs of Revenue	'
	Costs of Revenue
	Cost of revenue consists of the cost of subscription revenue and cost of professional services revenue.
	Cost of subscription revenue primarily consists of data fees, employee-related expenses (including salaries, benefits and stock-based compensation) related to hosting costs of our cloud-based service, cost of subcontractors, expenses for service delivery (which includes call center support), allocated overhead, the costs of data center capacity and depreciation of owned computer equipment and software.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	Cash and cash equivalents consist of highly liquid investments with original maturities of three months or less from the date of purchase. Our cash and cash equivalents generally consist of investments in money market funds, U.S. treasury securities and U.S. government-issued obligations. Cash and cash equivalents are stated at fair value.
Marketable Securities	'
	Marketable Securities
	Our marketable securities consist of U.S. agency obligations, U.S. treasury securities and money market funds, with maturities at the time of purchase of greater than three months. Marketable securities with remaining maturities in excess of one year are classified as noncurrent. We classify our marketable securities as available-for-sale at the time of purchase based on our intent and are recorded at their estimated fair value. Unrealized gains and losses for available-for-sale securities are recorded in other comprehensive income (loss). We evaluate our investments to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses and declines in value judged to be other than temporary are determined based on the specific identification method and are reported in other income, net in the condensed consolidated statements of operations.
Internal-use Software	'
	Internal-use Software
	For our development costs related to our cloud-based service, we capitalize costs incurred during the application development stage. Costs related to preliminary project and post-implementation stages are expensed as incurred. Capitalized software development costs are included as part of property, plant and equipment and are amortized on a straight-line basis over the technology's estimated useful life, which is generally three years. The amortization expense is recorded as a component of cost of subscription revenue.
	During the three and nine months ended September 30, 2014, we capitalized software costs totaling $0.2 million. All software development costs incurred in prior periods have been expensed.
Deferred Commissions	'
	Deferred Commissions
	Deferred commissions are the incremental costs that are directly associated with the noncancelable portion of cloud-based subscription service contracts with customers and consist of sales commissions paid to our direct sales force. The commissions are deferred and amortized over the noncancelable terms of the related contracts. The deferred commission amounts are recoverable through the future revenue streams under the noncancelable customer contracts. Amortization of deferred commissions is included in sales and marketing expense in the condensed consolidated statements of operations.
Deferred Revenue	'
	Deferred Revenue
	Deferred revenue primarily consists of professional services and cloud-based subscription services that have been billed in advance of revenue being recognized or the services have not been delivered. Additionally, deferred revenue consists of professional services that have been billed and delivered but the revenue is being deferred and recognized together with a cloud-based subscription contract as a single unit of accounting. We invoice our customers for our cloud-based subscription services based on the terms of the contract, which can be annual, quarterly or monthly installments. We invoice our customers for our professional services and the first year of communication services generally at contract execution. Deferred revenue that is anticipated to be recognized during the succeeding 12-month period is recorded as current deferred revenue, and the remaining portion is recorded as noncurrent.
Share-based Compensation	'
	Stock-based Compensation
	All stock-based compensation to employees is measured based on the grant-date fair value of the awards and recognized in our condensed consolidated statements of operations over the period during which the employee is required to perform services in exchange for the award (generally the vesting period of the award). We estimate the fair value of stock options granted using the Black-Scholes option valuation model. Compensation expense is recognized over the vesting period of the applicable award using the straight-line method.
	Compensation expense for non-employee stock options and warrants is calculated using the Black-Scholes option-pricing model and is recorded as the options vest. Options subject to vesting are required to be periodically revalued over their service period, which is generally the same as the vesting period.
Warranties and Indemnification	'
	Warranties and Indemnification
	Our cloud-based service is generally warranted to be performed in a professional manner and in a manner that will comply with the terms of the customer agreements.
	Our arrangements generally include certain provisions for indemnifying customers against liabilities if there is a breach of a customer’s data or if our service infringes a third party’s intellectual property rights. To date, we have not incurred any material costs as a result of such indemnifications and have not accrued any liabilities related to such obligations in the financial statements. We have entered into service-level agreements with certain customers warranting defined levels of performance and response and permitting those customers to receive credits for prepaid amounts related to subscription services in the event that we fail to meet those levels. To date, we have not experienced any significant failures to meet defined levels of performance and response as a result of those agreements.
	We have also agreed to indemnify our directors and executive officers for costs associated with any fees, expenses, judgments, fines and settlement amounts incurred by any of these persons in any action or proceeding to which any of those persons is, or is threatened to be, made a party by reason of the person’s service as a director or officer, including any action by us, arising out of that person’s services as our director or officer or that person’s services provided to any other company or enterprise at our request. We maintain director and officer insurance coverage that would generally enable us to recover a portion of any future amounts paid. We may also be subject to indemnification obligation by law with respect to the actions of our employees under certain circumstances and in certain jurisdiction
Recently Issued and Adopted Accounting Pronouncements	'
	Recently Issued and Adopted Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09 regarding ASC Topic 606, Revenue from Contracts with Customers. The standard provides principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance will be effective for us beginning January 1, 2017. Early adoption is not permitted. We are currently evaluating the accounting, transition and disclosure requirements of the standard and cannot currently estimate the financial statement impact of adoption.

Marketable_Securities_Tables

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Available-for-sale Securities	'
	At September 30, 2014 and December 31, 2013, respectively, marketable securities consisted of the following (in thousands):
		Amortized		Unrealized		Unrealized			Fair Value
		Cost		Gains		Losses
	September 30, 2014
	U.S. agency obligations	$	182,406	$	20	$	(12	)	$	182,414
	U.S. treasury securities	5,635		4		—			5,639
	Money market mutual funds	11,692		—		—			11,692
		199,733		24		(12		)	199,745
	Included in cash and cash equivalents	15,114		—		—			15,114
	Included in marketable securities	$	156,920	$	20	$	(9	)	$	156,931
	Included in marketable securities, noncurrent	$	27,699	$	4	$	(3	)	$	27,700
		Amortized		Unrealized		Unrealized			Fair Value
		Cost		Gains		Losses
	December 31, 2013
	U.S. agency obligations	$	35,996	$	6	$	(7	)	$	35,995
	U.S. treasury securities	6,020		2		—			6,022
	Money market mutual funds	18,082		—		—			18,082
		60,098		8		(7		)	60,099
	Included in cash and cash equivalents	18,082		—		—			18,082
	Included in marketable securities	$	42,016	$	8	$	(7	)	$	42,017

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value, Assets Measured on Recurring Basis	'
	The following tables present information about our assets that are measured at fair value on a recurring basis using the above input categories (in thousands):
		Level 1		Level 2		Total
	30-Sep-14
	Cash equivalents:
	Money market mutual funds	$	11,692	$	—	$	11,692
	Marketable securities:
	U.S. agency obligations	—		182,414		182,414
	U.S. treasury securities	—		5,639		5,639
		$	11,692	$	188,053	$	199,745
		Level 1		Level 2		Total
	December 31, 2013
	Cash equivalents:
	Money market mutual funds	$	18,082	$	—	$	18,082
	Marketable securities:
	U.S. agency obligations	—		35,995		35,995
	U.S. treasury securities	—		6,022		6,022
		$	18,082	$	42,017	$	60,099

Property_and_equipment_net_Tab

Property and equipment, net (Tables)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	Property and equipment consisted of the following (in thousands):
		As of
		September 30, 2014			December 31, 2013
	Leasehold improvements	$	1,043		$	924
	Computer equipment	2,635			2,024
	Software	824			263
	Capitalization of internal-use software	162			—
	Furniture and equipment	301			257
	Total	4,965			3,468
	Accumulated depreciation	(1,737		)	(837		)
	Property and equipment, net	$	3,228		$	2,631

Deferred_Revenue_Tables

Deferred Revenue (Tables)	9 Months Ended
	Sep. 30, 2014
Deferred Revenue Disclosure [Abstract]	'
Deferred Revenue, by Arrangement, Disclosure	'
	Deferred revenue consisted of the following (in thousands):
		As of
		September 30, 2014		December 31, 2013
	Subscription	$	12,387	$	3,810
	Professional services—implementation	2,891		1,835
	Professional services—communications	2,833		1,280
	Total current	18,111		6,925
	Subscription	3,379		1,489
	Professional services—implementation	4,209		2,443
	Professional services—communications	407		616
	Total noncurrent	7,995		4,548
	Total	$	26,106	$	11,473

Stockholders_Equity_Deficit_Ta

Stockholders' Equity (Deficit) (Tables)	9 Months Ended
	Sep. 30, 2014
Equity and Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Stock by Class	'
			As of September 30, 2014				As of December 31, 2013
			Shares			Shares Issued and	Shares		Shares Issued and	Liquidation
			Authorized			Outstanding	Authorized		Outstanding	Preference
	Convertible Preferred Stock:
		Series A	—			—	8,000,000		8,000,000	$	1,000,000
		Series A-1	—			—	10,000,000		10,000,000	3,000,000
		Series B	—			—	15,315,314		15,315,314	17,000,000
		Series C	—			—	14,594,598		14,594,598	60,000,000
		Series D	—			—	16,565,750		16,565,721	100,000,000
		Total	—			—	64,475,662		64,475,633	181,000,000
	Stockholders' equity:
		Preferred stock	10,000,000			—	—		—	—
		Class A common stock	200,000,000			62,622,110	95,000,000		10,994,074	—
		Class B common stock	800,000,000			27,307,588	95,000,000		—	—
		Total	1,010,000,000			89,929,698	254,475,662		75,469,707	$	181,000,000
Schedule of Share-based Compensation, Stock Options, Activity	'
	A summary of stock option activity for the nine months ended September 30, 2014 is as follows (in thousands, except share and per share amounts):
		Options			Weighted-		Aggregate
		Outstanding			Average		Intrinsic
					Exercise		Value
					Price
	Balance at December 31, 2013	16,455,404			$	1.22	$	91,192
	Stock option grants	4,132,429			$	12.51
	Stock options exercised	(1,693,338	)		$	1.14
	Stock options canceled	(1,664,236	)		$	3.38
	Balance at September 30, 2014	17,230,259			$	3.73	$	158,743
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	'
	The fair value of each option grant was estimated on the date of grant using the Black-Scholes option-valuation model with the following assumptions and fair value per share:
		Nine Months Ended September 30,
		2014		2013
	Volatility	60%		57.8%-60%
	Expected life (in years)	5.0-6.2		5.0-6.5
	Risk-free interest rate	1.53%-2.05%		0.7%-1.8%
	Dividend yield	—%		—%
	Weighted-average fair value of underlying common stock	$13.60		$1.44

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted	'
	The following table presents the calculation of basic and diluted net loss per share for our common stock (in thousands, except per share data):
		Three Months Ended September 30,										Nine Months Ended September 30,
		2014							2013			2014						2013
		Class A				Class B			Class A			Class A			Class B			Class A
	Net loss	$	(16,356	)		$	(3,843	)	$	(16,603	)	$	(55,833	)	$	(10,423	)	$	(42,209	)
	Weighted-average shares used to compute basic and diluted net loss per share	72,633				17,065			10,168			58,112			10,848			9,684
	Basic and diluted net loss per share	$	(0.23	)		$	(0.23	)	$	(1.63	)	$	(0.96	)	$	(0.96	)	$	(4.36	)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	'
	The following securities were excluded from the calculation of diluted net loss per share for common stock because their effect would have been anti-dilutive for the periods presented (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014		2013
	Convertible preferred stock	—			64,476			—		64,476
	Stock options and restricted common stock	17,230			13,615			17,230		13,615
	Warrants	115			—			115		—
		17,345			78,091			17,345		78,091

Organization_and_Description_o1

Organization and Description of Business (Details) (USD $)	9 Months Ended		0 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Mar. 19, 2014	Mar. 19, 2014
			IPO [Member]	IPO [Member]
				Class B [Member]
Class of Stock [Line Items]	'	'	'	'
Stock Issued During Period, Shares, New Issues	'	'	'	12.8
Shares Issued, Price Per Share	'	'	'	$16
Stock Issued During Period, Value, New Issues	'	'	$204,200,000	'
Proceeds from Issuance Initial Public Offering	186,162,000	0	185,600,000	'
Payments of Stock Issuance Costs, Underwriter Fees and Commissions	'	'	14,300,000	'
Deferred Offering Costs	'	'	$4,300,000	'

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014	Dec. 30, 2013
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]	'	'	'
Common Stock, Conversion Basis, Ratio	'	'	1
Capitalized software costs	$0.20	$0.20	'
Cloud-Based Subscription Service [Member]	'	'	'
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]	'	'	'
Revenue Recognition, Contractual Term of Services	'	'3 years	'
Communication Services [Member]	'	'	'
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]	'	'	'
Revenue Recognition, Contractual Term of Services	'	'1 year	'

Marketable_Securities_Details

Marketable Securities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$199,733	$60,098
Unrealized Gains	24	8
Unrealized Losses	-12	-7
Fair Value	199,745	60,099
Included in cash and cash equivalents [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	15,114	18,082
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	15,114	18,082
Included in marketable securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	156,920	42,016
Unrealized Gains	20	8
Unrealized Losses	-9	-7
Fair Value	156,931	42,017
U.S. agency obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	182,406	35,996
Unrealized Gains	20	6
Unrealized Losses	-12	-7
Fair Value	182,414	35,995
U.S. treasury securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	5,635	6,020
Unrealized Gains	4	2
Unrealized Losses	0	0
Fair Value	5,639	6,022
Money market mutual funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	11,692	18,082
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	$11,692	$18,082

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'	'
Available-for-sale Securities, Gross Realized Gain (Loss)	$0	$0
Available-for-sale Securities, Maturity Period	'	'1 year

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Assets Measured at Fair Value on a Recurring Basis (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Marketable securities:	'	'
Marketable securities	$199,745	$60,099
Money market mutual funds [Member]	'	'
Marketable securities:	'	'
Marketable securities	11,692	18,082
U.S. agency obligations [Member]	'	'
Marketable securities:	'	'
Marketable securities	182,414	35,995
U.S. treasury securities [Member]	'	'
Marketable securities:	'	'
Marketable securities	5,639	6,022
Fair Value, Measurements, Recurring	'	'
Marketable securities:	'	'
Assets, Fair Value Disclosure	199,745	60,099
Fair Value, Measurements, Recurring | Money market mutual funds [Member]	'	'
Cash equivalents:	'	'
Cash equivalents	11,692	18,082
Fair Value, Measurements, Recurring | U.S. agency obligations [Member]	'	'
Marketable securities:	'	'
Marketable securities	182,414	35,995
Fair Value, Measurements, Recurring | U.S. treasury securities [Member]	'	'
Marketable securities:	'	'
Marketable securities	5,639	6,022
Fair Value, Measurements, Recurring | Level 1 [Member]	'	'
Marketable securities:	'	'
Assets, Fair Value Disclosure	11,692	18,082
Fair Value, Measurements, Recurring | Level 1 [Member] | Money market mutual funds [Member]	'	'
Cash equivalents:	'	'
Cash equivalents	11,692	18,082
Fair Value, Measurements, Recurring | Level 1 [Member] | U.S. agency obligations [Member]	'	'
Marketable securities:	'	'
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 1 [Member] | U.S. treasury securities [Member]	'	'
Marketable securities:	'	'
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 2 [Member]	'	'
Marketable securities:	'	'
Assets, Fair Value Disclosure	188,053	42,017
Fair Value, Measurements, Recurring | Level 2 [Member] | Money market mutual funds [Member]	'	'
Cash equivalents:	'	'
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 [Member] | U.S. agency obligations [Member]	'	'
Marketable securities:	'	'
Marketable securities	182,414	35,995
Fair Value, Measurements, Recurring | Level 2 [Member] | U.S. treasury securities [Member]	'	'
Marketable securities:	'	'
Marketable securities	$5,639	$6,022

Property_and_equipment_net_Det

Property and equipment, net (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'	'	'	'
Depreciation Expense	$0.30	$0.20	$0.90	$0.40

Property_and_equipment_net_Sch

Property and equipment, net - Schedule of Property, Plant and Equipment (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property and Equipment	$4,965	$3,468
Capitalization of internal-use software	162	0
Accumulated depreciation	-1,737	-837
Property and equipment, net	3,228	2,631
Leasehold Improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and Equipment	1,043	924
Computer Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and Equipment	2,635	2,024
Software [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and Equipment	824	263
Furniture and Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and Equipment	$301	$257

Deferred_Revenue_Components_of

Deferred Revenue - Components of Deferred Revenue (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Revenue Arrangement [Line Items]	'	'
Total current	$18,111	$6,925
Total noncurrent	7,995	4,548
Total	26,106	11,473
Subscription [Member]	'	'
Deferred Revenue Arrangement [Line Items]	'	'
Total current	12,387	3,810
Total noncurrent	3,379	1,489
Professional Services - Implementation [Member]	'	'
Deferred Revenue Arrangement [Line Items]	'	'
Total current	2,891	1,835
Total noncurrent	4,209	2,443
Professional Services - Communications [Member]	'	'
Deferred Revenue Arrangement [Line Items]	'	'
Total current	2,833	1,280
Total noncurrent	$407	$616

Stockholders_Equity_Deficit_In

Stockholders' Equity (Deficit) - Initial Public Offering (Details) (IPO [Member], Class B [Member], USD $)	0 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 19, 2014
IPO [Member] | Class B [Member]	'
Class of Stock [Line Items]	'
Stock Issued During Period, Shares, New Issues	12.8
Shares Issued, Price Per Share	$16

Stockholders_Equity_Deficit_Su

Stockholders' Equity (Deficit) - Summary of Stock by Class (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Convertible Preferred Stock:	'	'
Shares Outstanding	0	64,475,633
Stockholders' equity:	'	'
Preferred Stock, Shares Authorized	10,000,000	0
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, Liquidation Preference	'	$0
Shares Authorized, including Temporary Equity	1,010,000,000	254,475,662
Shares Issued, including Temporary Equity	89,929,698	75,469,707
Shares Outstanding, including Temporary Equity	89,929,698	0
Preferred Stock, Liquidation Preference Including Temporary Equity, Value	'	181,000,000
Convertible Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	64,475,662
Shares Issued	0	64,475,633
Liquidation Preference	'	181,000,000
Series A Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	8,000,000
Shares Issued	0	8,000,000
Shares Outstanding	0	8,000,000
Liquidation Preference	'	1,000,000
Series A-1 Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	10,000,000
Shares Issued	0	10,000,000
Shares Outstanding	0	10,000,000
Liquidation Preference	'	3,000,000
Series B Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	15,315,314
Shares Issued	0	15,315,314
Shares Outstanding	0	15,315,314
Liquidation Preference	'	17,000,000
Series C Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	14,594,598
Shares Issued	0	14,594,598
Shares Outstanding	0	14,594,598
Liquidation Preference	'	60,000,000
Series D Preferred Stock [Member]	'	'
Convertible Preferred Stock:	'	'
Shares Authorized	0	16,565,750
Shares Issued	0	16,565,721
Shares Outstanding	0	16,565,721
Liquidation Preference	'	$100,000,000
Class A [Member]	'	'
Stockholders' equity:	'	'
Common Stock, Shares Authorized	200,000,000	95,000,000
Common Stock, Shares, Issued	62,622,110	10,994,074
Common Stock, Shares, Outstanding	62,622,110	0
Class B [Member]	'	'
Stockholders' equity:	'	'
Common Stock, Shares Authorized	800,000,000	95,000,000
Common Stock, Shares, Issued	27,307,588	0
Common Stock, Shares, Outstanding	27,307,588	0

Stockholders_Equity_Deficit_Em

Stockholders' Equity (Deficit) - Employee Equity Plans (Details) (Class B [Member])	Mar. 12, 2014	Mar. 13, 2014
	2014 Equity Incentive Plan [Member]	2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Common Stock, Capital Shares Reserved for Future Issuance	15,000,000	6,000,000

Stockholders_Equity_Deficit_Su1

Stockholders' Equity (Deficit) - Summary of Stock Option Activity (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014
Options Outstanding	'
Beginning Balance	16,455,404,000
Stock option grants	4,132,429,000
Stock options exercised	-1,693,338,000
Stock options canceled	-1,664,236,000
Ending Balance	17,230,259,000
Weighted- Average Exercise Price	'
Beginning Balance	$3.73
Stock option grants	$12.51
Stock options exercised	$1.14
Stock options canceled	$3.38
Ending Balance	$1.22
Aggregate Intrinsic Value	'
Beginning Balance	$91,192
Ending Balance	$158,743

Stockholders_Equity_Deficit_St

Stockholders' Equity (Deficit) - Stock Options Activity and Stock-based Compensation (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Equity and Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'
Stock Granted, Value, Share-based Compensation, Gross	$32.10	$4.10
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$26.50	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	'3 years 1 month 13 days	'

Stockholders_Equity_Deficit_As

Stockholders' Equity (Deficit) - Assumptions Related to Share-based Compensation (Details) (Stock Option [Member], USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Volatility	60.00%	'
Risk-free interest rate, minimum	1.53%	0.70%
Risk-free interest rate, maximum	2.05%	1.80%
Dividend yield	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$13.60	$1.44
Minimum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Volatility	'	57.80%
Expected life (in years)	'5 years	'5 years
Maximum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Volatility	'	60.00%
Expected life (in years)	'6 years 2 months 12 days	'6 years 6 months

Stockholders_Equity_Deficit_Wa

Stockholders' Equity (Deficit) - Warrants (Details) (USD $)	9 Months Ended		0 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 11, 2013	Sep. 30, 2014
			Class A [Member]	Class A [Member]
Class of Warrant or Right [Line Items]	'	'	'	'
Document Period End Date	30-Sep-14	'	'	'
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	'	'	175,000	'
Class of Warrant or Right, Exercise Price of Warrants or Rights	'	'	5	'
Class of Warrant or Right, Term	'	'	'10 years	'
Class of Warrant or Right, Percentage of Warrants Vested	'	'	'	70.00%
Class of Warrant or Right, Percentage of Warrants Unvested	'	'	'	30.00%
Expense related to warrant	$2,659	$0	'	'

Income_Taxes_Details

Income Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	0.00%	0.00%	0.00%	0.00%

Net_Loss_per_Share_Calculation

Net Loss per Share - Calculation of Basic and Diluted EPS for Common Stock (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]	'	'	'	'
Net loss	($20,199)	($16,603)	($66,256)	($42,209)
Weighted-average shares used to compute basic and diluted net loss per share	89,698	10,168	68,960	9,684
Basic and diluted net loss per share (in usd per share)	($0.23)	($1.63)	$0	$0
Class A [Member]	'	'	'	'
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]	'	'	'	'
Net loss	-16,356	-16,603	-55,833	-42,209
Weighted-average shares used to compute basic and diluted net loss per share	72,633	10,168	58,112	9,684
Basic and diluted net loss per share (in usd per share)	($0.23)	($1.63)	($0.96)	($4.36)
Class B [Member]	'	'	'	'
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]	'	'	'	'
Net loss	($3,843)	'	($10,423)	'
Weighted-average shares used to compute basic and diluted net loss per share	17,065	'	10,848	'
Basic and diluted net loss per share (in usd per share)	($0.23)	'	($0.96)	'

Net_Loss_per_Share_Summary_of_

Net Loss per Share - Summary of Antidilutive Securities (Details) (Class A [Member])	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	17,345	78,091	17,345	78,091
Convertible Preferred Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	64,476	0	64,476
Stock Options and Restricted Common Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	17,230	13,615	17,230	13,615
Warrants [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	115	0	115	0