Bandwidth (BAND) 10-Q 4 May 20 2020 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-38285
Entity Registrant Name	BANDWIDTH INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	56-2242657
Entity Address, Address Line One	900 Main Campus Drive
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27606
City Area Code	(800)
Local Phone Number	808-5150
Title of 12(b) Security	Class A Common Stock, par value $0.001 per share
Trading Symbol	BAND
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001514416
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Class A
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		19,432,593
Common Class B
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		4,427,151

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 491,982	$ 184,414
Restricted cash	25,878	590
Accounts receivable, net of allowance for doubtful accounts	37,072	30,187
Prepaid expenses and other current assets	10,149	9,260
Deferred costs	1,792	2,498
Total current assets	566,873	226,949
Property and equipment, net	43,905	41,654
Operating right-of-use asset	19,873	21,031
Intangible assets, net	6,439	6,569
Deferred costs, non-current	3,054	1,952
Other long-term assets	1,626	1,533
Goodwill	6,867	6,867
Deferred tax asset, net	16,639	34,861
Total assets	665,276	341,416
Current liabilities:
Accounts payable	5,325	4,190
Accrued expenses and other current liabilities	23,781	27,328
Current portion of deferred revenue	5,046	5,177
Advanced billings	4,851	4,167
Operating lease liability, current	4,973	4,876
Total current liabilities	43,976	45,738
Long-term lease obligations	18,486	19,868
Deferred revenue, net of current portion	6,272	5,720
Convertible senior notes	268,383	0
Total liabilities	337,117	71,326
Stockholders’ equity:
Class A and Class B common stock	23	24
Additional paid-in capital	334,777	275,553
Accumulated deficit	(6,586)	(5,528)
Accumulated other comprehensive income (loss)	(55)	41
Total stockholders’ equity	328,159	270,090
Total liabilities and stockholders’ equity	$ 665,276	$ 341,416

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 68,518	$ 53,321
Cost of revenue	36,359	28,766
Gross profit	32,159	24,555
Operating expenses:
Research and development	9,530	7,717
Sales and marketing	9,417	8,349
General and administrative	16,096	14,333
Total operating expenses	35,043	30,399
Operating loss	(2,884)	(5,844)
Other income, net	(906)	201
Loss before income taxes	(3,790)	(5,643)
Income tax benefit	2,732	7,635
Net income (loss)	$ (1,058)	$ 1,992
Net income (loss) per share
Basic (in usd per share)	$ (0.04)	$ 0.10
Diluted (in usd per share)	$ (0.04)	$ 0.09
Weighted average number of common shares outstanding:
Basic (in shares)	23,563,569	20,498,104
Diluted (in shares)	23,563,569	21,975,944

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders’ Equity - USD ($) $ in Thousands	Total	Conversion of Class B voting common stock to Class A voting common stock	Class A voting common stock	Class B voting common stock	Common stockClass A voting common stock	Common stockClass A voting common stockConversion of Class B voting common stock to Class A voting common stock	Common stockClass B voting common stock	Common stockClass B voting common stockConversion of Class B voting common stock to Class A voting common stock	Additional paid-in capital	Accumulated other comprehensive (loss) income	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2018					12,912,747		6,510,732
Beginning balance at Dec. 31, 2018	$ 108,770				$ 13		$ 6		$ 116,600	$ (1)	$ (7,848)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)					2,875,000
Issuance of common stock	147,391				$ 3				147,388
Costs in connection with offering	(785)								(785)
Exercises of vested stock options (in shares)					589,510
Exercises of vested stock options	3,935				$ 1				3,934
Vesting of restricted stock units (in shares)					105,367
Equity awards withheld for tax liability (in shares)					(16,585)
Equity awards withheld for tax liability	(938)								(938)
Conversion of stock (in shares)						57,230		(57,230)
Unrealized loss on marketable securities	8									8
Stock based compensation	1,676								1,676
Net income (loss)	1,992										1,992
Ending balance (in shares) at Mar. 31, 2019					16,523,269		6,453,502
Ending balance at Mar. 31, 2019	261,875				$ 17		$ 6		267,875	7	(6,030)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Costs in connection with offering	(49)								(49)
Exercises of vested stock options (in shares)					366,405
Exercises of vested stock options	2,446								2,446
Vesting of restricted stock units (in shares)					20,003
Equity awards withheld for tax liability (in shares)					(3,665)
Equity awards withheld for tax liability	(274)								(274)
Conversion of stock (in shares)						826,441		(826,441)
Conversion of stock		$ 0				$ 1		$ (1)
Unrealized loss on marketable securities	13									13
Foreign currency translation	12									12
Stock based compensation	1,630								1,630
Net income (loss)	3,472										3,472
Ending balance (in shares) at Jun. 30, 2019					17,732,453		5,627,061
Ending balance at Jun. 30, 2019	269,125				$ 18		$ 5		271,628	32	(2,558)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of vested stock options (in shares)					108,361
Exercises of vested stock options	868								868
Vesting of restricted stock units (in shares)					19,064
Equity awards withheld for tax liability (in shares)					(2,762)
Equity awards withheld for tax liability	(180)								(180)
Conversion of stock (in shares)						449,660		(449,660)
Unrealized loss on marketable securities	(21)									(21)
Foreign currency translation	(46)									(46)
Stock based compensation	1,654								1,654
Net income (loss)	(1,014)										(1,014)
Ending balance (in shares) at Sep. 30, 2019					18,306,776		5,177,401
Ending balance at Sep. 30, 2019	270,386				$ 18		$ 5		273,970	(35)	(3,572)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of vested stock options (in shares)					11,206
Exercises of vested stock options	108								108
Vesting of restricted stock units (in shares)					19,510
Equity awards withheld for tax liability (in shares)					(3,014)
Equity awards withheld for tax liability	(191)								(191)
Conversion of stock (in shares)						250,000		(250,000)
Conversion of stock		1				$ 1
Unrealized loss on marketable securities	1									1
Foreign currency translation	75									75
Stock based compensation	1,666								1,666
Net income (loss)	(1,956)										(1,956)
Ending balance (in shares) at Dec. 31, 2019			18,584,478	4,927,401	18,584,478		4,927,401
Ending balance at Dec. 31, 2019	270,090				$ 19		$ 5		275,553	41	(5,528)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of debt conversion option	104,553								104,553
Debt conversion option issuance costs, net of tax	(3,731)								(3,731)
Capped call option issuance costs	43,320								(43,320)
Exercises of vested stock options (in shares)					32,059
Exercises of vested stock options	244								244
Vesting of restricted stock units (in shares)					103,824
Equity awards withheld for tax liability (in shares)					(14,411)
Equity awards withheld for tax liability	(1,021)								(1,021)
Conversion of stock (in shares)						500,250		(500,250)
Conversion of stock		$ (1)						$ (1)
Foreign currency translation	(96)									(96)
Stock based compensation	2,499								2,499
Net income (loss)	(1,058)										(1,058)
Ending balance (in shares) at Mar. 31, 2020			19,206,200	4,427,151	19,206,200		4,427,151
Ending balance at Mar. 31, 2020	$ 328,159				$ 19		$ 4		$ 334,777	$ (55)	$ (6,586)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019
Cash flows from operating activities
Net income (loss)	$ (1,058)	$ (1,956)	$ 3,472	$ 1,992
Adjustments to reconcile net income (loss) to net cash used in operating activities
Depreciation and amortization	3,298			2,209
Right-of-use asset amortization	1,158			919
Accretion of bond discount	0			(119)
Amortization of debt discount and issuance costs	1,753			122
Stock-based compensation	2,499			1,676
Deferred taxes	(2,337)			(7,664)
Loss on disposal of property and equipment	233			296
Changes in operating assets and liabilities:
Accounts receivable	(6,899)			(3,889)
Prepaid expenses and other assets	(991)			(1,552)
Deferred costs	(396)			604
Accounts payable	304			(435)
Accrued expenses and other liabilities	(4,991)			(1,729)
Deferred revenue and advanced billings	1,105			(527)
Operating right-of-use liability	(1,285)			(938)
Net cash used in operating activities	(7,607)			(9,035)
Cash flows from investing activities
Purchase of property and equipment	(3,638)			(1,239)
Capitalized software development costs	(790)			(595)
Purchase of marketable securities	0			(50,990)
Proceeds from sales and maturities of marketable securities	0			9,000
Net cash used in investing activities	(4,428)			(43,824)
Cash flows from financing activities
Proceeds from the follow-on public offering, net of underwriting discounts	0			147,391
Payment of costs related to the follow-on public offering	0			(159)
Proceeds from issuance of convertible senior notes	400,000			0
Payment of debt issuance costs	(11,048)			(125)
Purchase of capped call	(43,320)			0
Proceeds from exercises of stock options	244			3,935
Value of equity awards withheld for tax liabilities	(960)			(589)
Net cash provided by financing activities	344,916			150,453
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(25)			0
Net increase in cash, cash equivalents, and restricted cash	332,856			97,594
Cash, cash equivalents, and restricted cash, beginning of period	185,004		$ 139,095	41,501
Cash, cash equivalents, and restricted cash, end of period	517,860	$ 185,004		139,095
Supplemental disclosure of cash flow information
Cash paid during the year for interest	0			33
Cash paid (refunded) for taxes	(229)			114
Supplemental disclosure of noncash investing and financing activities
Purchase of property and equipment, accrued but not paid	2,595			1,768
Effect of ASC 606 implementation	0			549
Equity awards withheld for tax liabilities, accrued but not paid	238			349
Payment of debt issuance costs, accrued but unpaid	$ 875			$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,058)	$ 1,992
Other comprehensive income (loss)
Unrealized gain on marketable securities, net of income taxes	0	8
Foreign currency translation, net of income taxes	(96)	0
Other comprehensive income (loss)	(96)	8
Total comprehensive income (loss)	$ (1,154)	$ 2,000

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Bandwidth Inc. (together with its subsidiaries, “Bandwidth” or the “Company”) was founded in July 2000 and incorporated in Delaware on March 29, 2001. The Company’s headquarters are located in Raleigh, North Carolina. The Company is a cloud-based, software-powered communications platform-as-a-service (“CPaaS”) provider that enables enterprises to create, scale and operate voice or messaging communications services across any mobile application or connected device. The Company has two operating and reportable segments, CPaaS and Other. CPaaS revenue is derived from usage and monthly services fees charged for usage of Voice, Messaging, 911 and Phone Numbers solutions through the Company’s proprietary CPaaS software application programming interfaces. Other revenue consists of fees charged for services provided such as: SIP trunking, data resale, and a hosted Voice-over Internet Protocol (“VoIP”). The Other segment also includes revenue from traffic generated by other carriers, SMS registration fees and other miscellaneous product lines.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company's Annual Report on Form 10-K filed with the SEC on February 21, 2020. The condensed consolidated balance sheet as of December 31, 2019, included herein, was derived from the audited financial statements as of that date, but does not include all disclosures, including certain notes required by GAAP on an annual reporting basis. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial position, results of operations, comprehensive income (loss) and cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full year 2020 or any future period. Reclassification The Company reclassified certain prior year amounts to conform to the current year presentation. These reclassifications had no impact on the previously reported total assets, liabilities, stockholder’s deficit or net income. Principles of Consolidation The condensed consolidated financial statements include the accounts of Bandwidth Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the amounts reported in these financial statements and accompanying notes. These estimates in the condensed consolidated financial statements include, but are not limited to, allowance for doubtful accounts, reserve for sales credits, recoverability of long lived and intangible assets, discount rates used in the valuation of right-of-use assets and lease liabilities, the fair value of the liability and equity components of the Company’s Convertible Notes (as defined herein), estimated period of benefit, valuation allowances on deferred tax assets, certain accrued expenses, and contingencies. Although the Company believes that the estimates it uses are reasonable, due to the inherent uncertainty involved in making these estimates, actual results reported in future periods could differ from those estimates. Effective January 1, 2020, due to the continued growth in customers and low churn rates, the Company updated its calculation of the estimated period of benefit for nonrefundable upfront fees from 3 years to 4 years. For the three months ended March 31, 2020, the Company reduced total revenue and cost of revenue by approximately $439 and $319, respectively, related to the change in the estimated period of benefit. Cash and Cash Equivalents The Company classifies all highly liquid investments with stated maturities of three months or less from the date of purchase as cash equivalents and all highly liquid investments with stated maturities of greater than three months from the date of purchase as current marketable securities. Cash deposits are primarily in financial institutions in the US. However, cash for monthly operating costs of international operations are deposited in banks outside the US. The Company has a policy of making investments only with commercial institutions that have at least an investment grade credit rating. The Company invests its cash primarily in government securities and obligations, corporate debt securities, money market funds and reverse repurchase agreements (“RRAs”). RRAs are collateralized by deposits in the form of Government Securities and Obligations for an amount not less than 102% of their value. The Company does not record an asset or liability as the Company is not permitted to sell or repledge the associated collateral. The Company has a policy that the collateral has at least an “A” (or equivalent) credit rating. The Company utilizes a third-party custodian to manage the exchange of funds and ensure that collateral received is maintained at 102% of the value of the RRAs on a daily basis. RRAs with stated maturities of greater than three months from the date of purchase are classified as marketable securities. Restricted Cash Restricted cash consists primarily of cash deposited into a savings account with a financial institution as collateral for the Company’s obligations under the Convertible Notes, as well as customer deposits, employee withholding tax liability and employee benefits contributions not yet remitted. The Company has classified this asset as a short-term asset in order to match the expected period of restriction. See Note 8, “Debt” to these condensed consolidated financial statements, for further information. Accounts Receivable and Current Expected Credit Losses Accounts receivable are stated at realizable value, net of an allowance for doubtful accounts, which includes a reserve for expected credit losses. The allowance for doubtful accounts is based on management’s assessment of the collectability of its customer accounts. The Company regularly reviews the composition of the accounts receivable aging, historical bad debts, changes in payment patterns, customer creditworthiness, current economic trends, and reasonable and supportable forecasts about the future. Relevant risks characteristics include customer size and historical loss patterns. Management has evaluated the expected credit losses related to trade accounts receivable and determined that allowances of approximately $769 and $883 for uncollectible accounts and customer balances that are disputed were required as of December 31, 2019 and March 31, 2020, respectively. Refer to Note 4, “Financial Statement Components” to these condensed consolidated financial statements, for a rollforward of the components of the allowance for doubtful accounts as of December 31, 2019 and March 31, 2020. Refer to the Recently Adopted Accounting Standard section for the adoption of ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses . The Company includes unbilled receivables in its accounts receivable balance. Generally, these receivables represent services provided to customers, which will be billed in the next billing cycle. All amounts are considered collectible and billable. As of December 31, 2019 and March 31, 2020, unbilled receivables were $16,200 and $20,788, respectively. Concentration of Credit Risk Financial instruments that are exposed to concentration of credit risk consist primarily of cash and cash equivalents, marketable securities and trade accounts receivable. Cash deposits may be in excess of insured limits. The Company believes that the financial institutions that hold its cash deposits are financially sound and, accordingly, minimal credit risk exists with respect to these balances. With regard to customers, credit evaluation and account monitoring procedures are used to minimize the risk of loss. The Company believes that no additional credit risk beyond amounts provided for by the allowance for doubtful accounts are inherent in accounts receivable. As of December 31, 2019, no individual customer represented more than 10% of the Company’s accounts receivable, net of allowance for doubtful accounts. As of March 31, 2020, one individual customer represented approximately 15% of the Company’s accounts receivable, net of allowance for doubtful accounts. For the three months ended March 31, 2019 and 2020, no individual customer represented more than 10% of the Company’s total revenue. Recently Adopted Accounting Standards In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ( “ ASU ” ) 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract . This standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 is effective for interim and annual reporting periods beginning after December 15, 2019. As a result of the Company ’ s prospective adoption of this standard, the Company capitalized i mplementation costs related to cloud computing arrangements of $272 as of March 31, 2020. See Note 6, “Property and Equipment” to these condensed consolidated financial statements, for additional details. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, which eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information and modifies some disclosure requirements. ASU 2018-13 is effective for interim and annual reporting periods beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of this standard did not have a material impact on the Company ’ s financial statements. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment , which simplifies the accounting for goodwill impairment. The ASU removes the second step of the goodwill impairment test that requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. ASU 2017-04 is effective for interim and annual reporting periods beginning after December 15, 2019. The adoption of this standard did not have a material impact on the Company’s financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments–Credit Losses: Measurement of Credit Losses on Financial Instruments , which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which will generally result in earlier recognition of allowances for losses. In November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses , which clarifies that receivables arising from operating leases are not within the scope of Topic 326, Financial Instruments – Credit Losses. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with Topic 842, Leases. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, which clarifies how to apply certain aspects of the new credit losses standard. In November 2019, the FASB issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates , which amends certain effective dates for the new standard. In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , which clarifies how to apply certain aspects of the new credit losses standard. The accounting standard is effective for annual and interim periods beginning after December 15, 2019. The Company adopted this standard for financial assets measured at amortized cost, including trade receivables. Results for the reporting periods beginning after January 1, 2020 are presented under ASC 326, while prior period amounts continue to be reported in accordance with previously applicable GAAP. The adoption of this standard did not have a material impact on the Company’s financial statements. Recent Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted, including adoption in an interim period. The Company is evaluating the effect of adopting this new accounting guidance, but does not expect adoption will have a material impact on its financial statements.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate fair value as of December 31, 2019 and March 31, 2020 because of the relatively short duration of these instruments. The Company evaluated its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level in which to classify them for each reporting period. The following table summarizes the assets measured at fair value as of December 31, 2019 and March 31, 2020: Fair value measurements on a recurring basis Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents: Money market account $ 25,000 $ — $ — $ 25,000 Time deposits 75,250 — — 75,250 Total financial assets $ 100,250 $ — $ — $ 100,250 Fair value measurements on a recurring basis Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents: Money market account $ 135,113 $ — $ — $ 135,113 Time deposits 255,515 — — 255,515 Total financial assets $ 390,628 $ — $ — $ 390,628 As of March 31, 2020, the fair value of the Convertible Notes, as further described in Note 8, “Debt”, was approximately $384,490. The fair value was determined based on the closing price for the Convertible Notes on the last trading day of the reporting period and is considered as Level 2 in the fair value hierarchy. The Company classifies its marketable securities as current assets as they are available for current operating needs. There were no marketable securities as of March 31, 2020. The money market account is included in cash and cash equivalents in the condensed consolidated balance sheets as of December 31, 2019 and March 31, 2020. During the three months ended March 31, 2019 and 2020, there were $9,000 and $0 in maturities of marketable securities, respectively. Interest earned on marketable securities was $3 and $0 for the three months ended March 31, 2019 and 2020, respectively, and is recorded within other income (expense), net, in the accompanying condensed consolidated statements of operations.

Financial Statement Components

Financial Statement Components	3 Months Ended
	Mar. 31, 2020
Financial Statement Components [Abstract]
Financial Statement Components	4. Financial Statement Components Accounts receivable, net of allowance for doubtful accounts consist of the following: As of December 31, As of March 31, 2019 2020 Trade accounts receivable $ 14,692 $ 16,553 Unbilled accounts receivable 16,200 20,788 Allowance for doubtful accounts (769) (883) Other accounts receivable 64 614 Total accounts receivable, net $ 30,187 $ 37,072 Components of allowance for doubtful accounts are as follows: Three months ended March 31, 2019 2020 Allowance for doubtful accounts: Balance, beginning of period $ (906) $ (769) Charged to bad debt expense (132) (189) Deductions (1) 20 75 Balance, end of period $ (1,018) $ (883) ________________________ (1) Write off of uncollectible accounts after all collection efforts have been exhausted. Accrued expenses and other current liabilities consisted of the following: As of December 31, As of March 31, 2019 2020 Accrued expense $ 12,701 $ 13,250 Accrued compensation and benefits 8,284 4,378 Accrued sales, use, and telecom related taxes 5,439 5,006 Other accrued expenses 904 1,147 Total accrued expenses and other current liabilities $ 27,328 $ 23,781

Right-of-Use Asset and Lease Li

Right-of-Use Asset and Lease Liabilities	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Right-of-Use Asset and Lease Liabilities	5. Right-of-Use Asset and Lease Liabilities In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). Under the new standard, lessees are required to recognize in the balance sheet the right-of-use (“ROU”) assets and lease liabilities that arise from operating leases. As a result of the Company no longer qualifying as an “emerging growth company” based on its public float as of the end of the fiscal quarter ended June 30, 2019, the ASU was adopted as of December 31, 2019 with an effective date as of the beginning of the Company’s fiscal year, January 1, 2019. The standard was applied to the operating leases that existed on that date using the optional alternative method on a prospective basis. Prior year comparative financial information was recast under the new standard to be presented under ASC 842. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The Company determines if an arrangement is a lease at inception. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company did not have any finance leases as of March 31, 2020. The Company presents the operating leases in long-term assets and current and long-term liabilities in the accompanying condensed consolidated balance sheet as of March 31, 2020. The Company sub-leases approximately 17,073 square feet of office space to a related party, Republic Wireless, Inc. ( “ Republic ” ). Future minimum sub-lease receipts required under the non-cancellable lease are as follows: As of March 31, 2020 2020 (remaining) $ 337 2021 457 2022 249 $ 1,043 As of March 31, 2020, the Company had six leased properties, with remaining lease terms of 2.33 years to 5.42 years, some of which include options to extend the leases for up to 5 years. None of the options to extend the leases are recognized in operating lease ROU assets or lease liabilities. None of the leases include options to terminate the lease. The components of lease expense recorded in the condensed consolidated statement of operations were as follows: Three months ended March 31, 2019 2020 Operating lease cost $ 1,218 $ 1,461 Sublease income (1) (251) (96) Total net lease cost $ 967 $ 1,365 ________________________ (1) See Note 15, “Related Parties” to these condensed consolidated financial statements, for additional details on sublease income. Supplemental balance sheet information related to leases was as follows: As of December 31, As of March 31, Leases Classification 2019 2020 Assets: Operating lease assets Operating ROU asset, net of accumulated amortization (1) $ 21,031 $ 19,873 Total leased assets $ 21,031 $ 19,873 Liabilities: Current Operating Operating lease liability, current $ 4,876 $ 4,973 Non-current Operating Operating lease liability, non-current 19,868 18,486 Total lease liabilities $ 24,744 $ 23,459 ________________________ (1) Operating lease assets are recorded net of accumulated amortization of $4,269 and $5,427 as of December 31, 2019 and March 31, 2020, respectively. Supplemental cash flow and other information related to leases was as follows: Three months ended March 31, 2019 2020 Cash paid for amounts included in the measurement of operating lease liabilities $ 938 $ 1,285 Weighted average remaining operating lease term (in years) 5.04 4.11 Weighted average operating lease discount rate 5.11 % 4.99 % Maturities of operating lease liabilities were as follows: As of March 31, 2020 2020 (remaining) $ 4,319 2021 6,587 2022 6,302 2023 5,926 2024 1,987 2025 949 Total lease payments 26,070 Less: imputed interest (2,591) Less: accrued lease incentive (20) Total lease obligations 23,459 Less: current obligations (4,973) Long-term lease obligations $ 18,486

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment, net consisted of the following: As of December 31, As of March 31, 2019 2020 Furniture and fixtures $ 2,373 $ 2,387 Computer and office equipment 4,627 4,725 Telecommunications equipment 44,324 48,460 Leasehold improvements 5,263 5,853 Software 2,018 2,027 Internal-use software development 17,952 18,512 Automobile 10 10 Total cost 76,567 81,974 Less—accumulated depreciation (34,913) (38,069) Total property and equipment, net $ 41,654 $ 43,905 The Company capitalized $595 and $790 of software development costs in the three months ended March 31, 2019 and 2020, respectively. Amortization expense related to capitalized software development costs were $789 and $582 for the three months ended March 31, 2019 and 2020, respectively. As of March 31, 2020, unamortized implementation costs related to cloud computing arrangements are $272, of which $58 are included in prepaid expenses and other current assets and $214 are included in other long-term assets. The Company recognized depreciation expense, which includes amortization of capitalized software development costs, as follows: Three months ended March 31, 2019 2020 Cost of revenue $ 1,293 $ 2,334 Research and development 69 115 Sales and marketing 28 29 General and administrative 689 690 Total depreciation expense $ 2,079 $ 3,168

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible assets, net consisted of the following as of December 31, 2019: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,591) $ 5,805 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,524) $ 6,569 Intangible assets, net consisted of the following as of March 31, 2020: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,721) $ 5,675 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,654) $ 6,439 Amortization expense for definite lived intangible assets was $130 for the three months ended March 31, 2019 and 2020. The remaining amortization period for definite lived intangible assets is 11 years. Future estimated amortization expense for definite lived intangible assets is as follows: As of March 31, 2020 2020 (remaining) $ 390 2021 520 2022 520 2023 520 2024 520 Thereafter 3,205 $ 5,675

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	8. Debt Revolving Loan On February 25, 2020, the Company entered into a waiver agreement with respect to its revolving loan (the “Credit Facility”) with KeyBank National Association and Pacific Western Bank, which provides for consent to accommodate the issuance of the Convertible Notes and entry into the Capped Calls (as defined below). The waiver agreement (“Cash Collateral Requirement”) requires the Company to covenant with KeyBank National Association and Pacific Western Bank to deposit an amount of funds into a controlled account, which will restrict the ability to use such funds until the Credit Facility is paid in full or terminated. If the Company fails to comply with these covenants or to make payments under its indebtedness when due, the Company would be in default under that indebtedness, which could, in turn, result in that indebtedness becoming immediately payable in full. As of December 31, 2019, unamortized debt issuance costs were $125, of which $70 were in included in prepaid expenses and other current assets and $55 were included in other long-term assets. As of March 31, 2020, the outstanding debt issuance costs are $107, of which $64 are included in prepaid expenses and other current assets and $43 are included in other long-term assets. As of December 31, 2019 and March 31, 2020, the Company had $0 outstanding on the Credit Facility and was in compliance with all financial and non-financial covenants for all periods presented. The available borrowing capacity under the Credit Facility was $25,000 as of March 31, 2020. Convertible Senior Notes and Capped Call Transactions On February 28, 2020, the Company issued $400,000 aggregate principal amount of 0.25% Convertible Notes due March 1, 2026 in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act (the “Convertible Notes”). The interest on the Convertible Notes is payable semi-annually in arrears on March 1 and September 1 of each year, beginning on September 1, 2020. The Convertible Notes may bear special interest under specified circumstances relating to the Company's failure to comply with its reporting obligations under the indenture governing the Convertible Notes (the “indenture”) or if the Convertible Notes are not freely tradeable as required by the indenture. The Convertible Notes will mature on March 1, 2026, unless earlier repurchased, redeemed by the Company, or converted pursuant to their terms. The total net proceeds from the Convertible Notes, after deducting initial purchaser discounts, costs related to the Capped Calls, and debt issuance costs, paid or payable by the Company, were approximately $344,757. Each $1 principal amount of the Convertible Notes is initially convertible into 10.9857 shares of the Company's Class A common stock, par value $0.001 per share, which is equivalent to an initial conversion price of approximately $91.03 per share. The conversion rate is subject to adjustment upon the occurrence of certain specified events but will not be adjusted for any accrued and unpaid special interest. In addition, upon the occurrence of a make-whole fundamental change, as defined in the indenture, the Company will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert its Convertible Notes in connection with such make-whole fundamental change or during the relevant redemption period. The Convertible Notes will be redeemable in whole or in part at the Company's option on or after March 6, 2023, but before the 40th scheduled trading day before the maturity date, at a cash redemption price equal to 100% of the principal amount of the Convertible Notes to be redeemed, plus accrued and unpaid interest, if any, if the last reported sale price of the Class A common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading days ending on, and including, the trading day immediately before the date the redemption notices were sent; and the trading day immediately before such notices were sent. Prior to the close of business on the business day immediately preceding September 1, 2025, the Convertible Notes may be convertible at the option of the holders only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2020 (and only during such calendar quarter), if the last reported sale price per share of the Company's Class A common stock exceeds 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) in which the trading price per $1 principal amount of Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company's Class A common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on its Class A common stock (4) if the Company calls such Convertible Notes for redemption; and (5) at any time from, and including, September 1, 2025 until the close of business on the second scheduled trading day immediately before the maturity date. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of Class A common stock, or a combination of cash and shares of Class A common stock, at the Company's election. It is the Company's current intent to settle the principal amount of the Convertible Notes with cash. During the three months ended March 31, 2020, the conditions allowing holders of the Convertible Notes to convert were not met. No sinking fund is provided for the Convertible Notes. Upon the occurrence of a fundamental change (as defined in the indenture) prior to the maturity date, holders may require the Company to repurchase all or a portion of the Convertible Notes for cash at a price equal to the principal amount of the Convertible Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date. The Convertible Notes are the senior, unsecured obligations of the Company and are equal in right of payment with the Company’s existing and future senior unsecured indebtedness, senior in right of payment to the Company’s existing and future indebtedness that is expressly subordinated to the Convertible Notes and effectively subordinated to the Company’s existing and future senior secured indebtedness (including the Company’s $25,000 Credit Facility), to the extent of the value of the collateral securing that indebtedness. The Convertible Notes will be structurally subordinated to all existing and future indebtedness and other liabilities, including trade payables, and preferred equity, if any, of the Company’s subsidiaries. In accounting for the issuance of the Convertible Notes, the Company separated the Convertible Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was $125,160 and was determined by deducting the fair value of the liability component from the par value of the Convertible Notes. The difference represents the debt discount that is amortized to interest expense at an effective interest rate of 6.763% over the term of the Convertible Notes. The carrying amount of the equity component was $57,502 and is recorded in additional paid-in-capital. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount, or the debt discount, is amortized to interest expense at an annual effective interest rate of 6.805% over the contractual terms of the Convertible Notes. In accounting for the transaction costs related to the Convertible Notes, the Company allocated the total amount incurred to the liability and equity components of the Convertible Notes based on the proportion of the proceeds allocated to the debt and equity components. Issuance costs attributable to the liability component were approximately $8,192, were recorded as an additional debt discount and are amortized to interest expense using the effective interest method over the contractual terms of the Convertible Notes. Issuance costs attributable to the equity component of $3,731 were netted with the equity component in stockholders’ equity. The net carrying amount of the liability component of the Convertible Notes was as follows: As of March 31, 2020 Principal $ 400,000 Unamortized discount (123,531) Unamortized debt issuance costs (8,086) Net carrying amount $ 268,383 The net carrying amount of the equity component of the Convertible Notes was as follows: As of March 31, 2020 Proceeds allocated to the conversion options (debt discount) $ 125,160 Issuance costs (3,731) Net carrying amount $ 121,429 The following table sets forth the interest expense recognized related to the Convertible Notes: As of March 31, 2020 Contractual interest expense $ 96 Amortization of debt issuance costs 1,629 Amortization of debt discount 106 Total interest expense related to the Convertible Notes $ 1,831 In connection with the offering of the Convertible Notes, the Company entered into privately negotiated capped call transactions with certain counterparties (the “Capped Calls”). The Capped Calls each have an initial strike price of approximately $91.03 per share, subject to certain adjustments, which corresponds to the initial conversion price of the Convertible Notes. The Capped Calls have initial cap prices of $137.40 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, approximately 4,394,276 shares of Class A common stock. The Capped Calls are generally intended to reduce or offset the potential dilution to the Class A common stock upon any conversion of the Convertible Notes with such reduction or offset, as the case may be, subject to a cap based on the cap price. The Capped Calls expire on the earlier of (i) the last day on which any convertible securities remain outstanding and (ii) March 1, 2026, subject to earlier exercise. The Capped Calls are subject to either adjustment or termination upon the occurrence of specified extraordinary events affecting the Company, including a merger event, a tender offer, and a nationalization, insolvency or delisting involving the Company. In addition, the Capped Calls are subject to certain specified additional disruption events that may give rise to a termination of the Capped Calls, including changes in law, insolvency filings, and hedging disruptions. The Capped Call transactions are recorded in stockholders’ equity and are not accounted for as derivatives. The net cost of $43,320 incurred to purchase the Capped Calls was recorded as a reduction to additional paid-in capital in the accompanying condensed consolidated balance sheets.

Segment and Geographic Informat

Segment and Geographic Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment and Geographic Information	9. Segment and Geographic Information The Company has two reportable segments, CPaaS and Other. Segments are primarily evaluated based on revenue and gross profit. The Company does not allocate operating expenses, interest expense or income tax expense to its segments. Accordingly, the Company does not report such information. Additionally, the Chief Operating Decision Maker does not evaluate the Company’s operating segments using discrete asset information. The segments share the majority of the Company’s assets. Therefore, no segment asset information is reported. Three months ended March 31, 2019 2020 CPaaS Revenue $ 45,013 $ 59,121 Cost of revenue 25,300 31,892 Gross profit $ 19,713 $ 27,229 Other Revenue $ 8,308 $ 9,397 Cost of revenue 3,466 4,467 Gross profit $ 4,842 $ 4,930 Consolidated Revenue $ 53,321 $ 68,518 Cost of revenue 28,766 36,359 Gross profit $ 24,555 $ 32,159 The Company's long-lived assets were primarily held in the United States as of December 31, 2019 and March 31, 2020. As of December 31, 2019 and March 31, 2020, long-lived assets held outside of the United States were $2,924 and $2,437, respectively. The Company generates its revenue primarily in the United States. Revenue by geographic area is detailed in the table below (which is determined based on the customer billing address): Three months ended March 31, 2019 2020 CPaaS United States $ 44,944 $ 57,398 International 69 1,723 Total $ 45,013 $ 59,121 Other United States $ 8,229 $ 9,125 International 79 272 Total $ 8,308 $ 9,397

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity Preferred Stock As of December 31, 2019 and March 31, 2020, the Company had authorized 10,000,000 shares of undesignated preferred stock, par value $0.001, of which no shares were issued and outstanding. Common Stock As of December 31, 2019 and March 31, 2020, the Company had authorized 100,000,000 shares of Class A common stock, par value $0.001 per share, with one vote per share and 20,000,000 shares of Class B common stock, par value $0.001 per share, with ten votes per share. As of December 31, 2019, 18,584,478 and 4,927,401 shares of Class A common stock and Class B common stock, respectively, were issued and outstanding. As of March 31, 2020, 19,206,200 and 4,427,151 shares of Class A common stock and Class B common stock, respectively, were issued and outstanding. Shares of Class B common stock are convertible into shares of Class A common stock upon the stockholder’s voluntary written notice to the Company’s transfer agent or a transfer by the stockholder, subject to limited exceptions for transfers for estate planning purposes. Reserved Shares The Company had reserved shares of Class A common stock for issuance under stock-based award agreements as follows: As of December 31, As of March 31, 2019 2020 Stock options issued and outstanding 853,399 820,966 Nonvested restricted stock units issued and outstanding 392,351 494,009 Stock-based awards available for grant under the 2017 Plan 1,310,354 2,034,096 2,556,104 3,349,071

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Based Compensation	11. Stock Based Compensation 2010 Stock Option Plan As of July 26, 2010, the Company adopted the 2010 Equity Compensation Plan (the “2010 Plan”). On November 9, 2017, the 2010 Plan was terminated in connection with the Company’s initial public offering. Accordingly, no shares are available for future issuance under the 2010 Plan. However, the 2010 Plan continues to govern the terms and conditions of the outstanding awards granted thereunder. 2017 Incentive Award Plan The Company’s 2017 Incentive Award Plan (the “2017 Plan”) became effective on November 9, 2017. The 2017 Plan provides for the grant of stock options, including incentive stock options and non-qualified stock options, stock appreciation rights, restricted stock, dividend equivalents, restricted stock units, and other stock or cash based awards to employees, consultants and directors of the Company. A total of 1,050,000 shares of the Company’s Class A common stock were originally reserved for issuance under the 2017 Plan. These available shares automatically increase each January 1, beginning on January 1, 2018, by 5% of the number of shares of the Company’s Class A common stock outstanding on the final day of the immediately preceding calendar year. On January 1, 2020, the shares available for grant under the 2017 Plan were automatically increased by 929,224 shares. The terms of the stock option grants are determined by the Company’s Board of Directors. The Company’s stock options vest based on terms of the stock option agreements, which is generally over four years. The stock options have a contractual life of ten years. Restricted stock units (“RSUs”) granted under the 2017 Plan are subject to a time-based vesting condition. The compensation expense related to these awards is based on the grant date fair value of the RSUs and is recognized on a ratable basis over the applicable service period. The Company granted RSUs to its non-employee Board of Directors, some of which vested immediately while others vest 25% as of each calendar quarter immediately following the grant date. Certain RSUs awarded to executives vest over four years with 50% vesting in the first year in 12.5% increments on each calendar quarter immediately following the grant date and the remaining 50% earned over years two, three and four. Other RSUs awarded to executives and employees generally are earned over a service period of four years. Stock Options The following summarizes the stock option activity for the periods presented: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2019 853,399 $ 8.07 3.41 $ 47,770 Granted — — Exercised (32,059) 7.61 2,136 Forfeited or cancelled (374) 19.51 Outstanding as of March 31, 2020 820,966 $ 8.09 3.16 $ 48,604 Options vested and exercisable at March 31, 2020 731,316 $ 7.29 2.67 $ 43,879 Options vested and expected to vest as of March 31, 2020 820,106 $ 8.08 3.15 $ 48,559 Aggregate intrinsic value is computed based on the difference between the option exercise price and the fair value of the Company’s common stock as of March 31, 2020, based on the Company’s Class A common stock price as reported on the NASDAQ Global Select Market. No options were granted for the three months ended March 31, 2019 and 2020. The total estimated grant date fair value of options vested was $57 and $46 for the three months ended March 31, 2019 and 2020, respectively. As of March 31, 2020, total unrecognized compensation cost related to all non-vested stock options was $410, which will be amortized over a weighted-average period of 1.23 years. Restricted Stock Units The following summarizes the RSU activity for the periods presented: Number of awards outstanding Weighted-average grant date fair value (per share) Nonvested RSUs as of December 31, 2019 392,351 $ 35.22 Granted 208,441 64.16 Vested (103,824) 34.37 Forfeited or cancelled (2,959) 50.05 Nonvested RSUs as of March 31, 2020 494,009 $ 47.72 As of March 31, 2020, total unrecognized compensation cost related to non-vested RSUs was $22,083, which will be amortized over a weighted-average period of 3.13 years. Stock-Based Compensation Expense The Company recognized total stock-based compensation expense as follows: Three months ended March 31, 2019 2020 Cost of revenue $ 56 $ 175 Research and development 372 453 Sales and marketing 320 395 General and administrative 928 1,476 Total $ 1,676 $ 2,499

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Operating Leases The Company leases office space under operating lease agreements that expire over the next 5.42 years. See Note 5, “Right-of-Use Asset and Lease Liabilities” to the condensed consolidated financial statements, for additional details on the Company's operating lease commitments. Contractual Obligations On October 25, 2015, the Company entered into an agreement with a telecommunications service provider. The service agreement requires the Company to pay a monthly recurring charge beginning on January 1, 2016 associated with the services received. The service agreement is non-cancellable and contains annual minimum commitments of $1,200, to be fulfilled over five years or for as long as the Company continues to receive services from this vendor. In addition, as of March 31, 2020, the Company has $9,720 in other non-cancellable purchase obligations, consisting of primarily network equipment maintenance and software license contracts, of which $5,404 will be fulfilled within one year. Legal Matters The Company is involved as a defendant in various lawsuits alleging that the Company failed to bill, collect and remit certain taxes and surcharges associated with the provision of 911 services pursuant to applicable laws in various jurisdictions. In August 2016, the Company received a Civil Investigative Demand from the Consumer Protection Division of the North Carolina Department of Justice, though the Company has not been served with a complaint in connection with that investigation. The North Carolina Department of Justice is investigating the billing, collection and remission of certain taxes and surcharges associated with 911 service pursuant to applicable laws of the State of North Carolina.

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended
	Mar. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plan	13. Employee Benefit Plan The Company sponsors a defined contribution 401(k) plan, which allows eligible employees to defer a portion of their compensation. The Company, at its discretion, may make matching contributions. The Company made matching contributions of $513 and $634 for the three months ended March 31, 2019 and 2020, respectively.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes At the end of each interim reporting period, the Company determines the income tax provision by using an estimate of the annual effective tax rate, adjusted for discrete items occurring in the quarter. The effective income tax rate reflects the effect of federal and state income taxes and the permanent impacts of differences in book and tax accounting. The Company’s effective tax rate was 135.2% and 72.1% for the three months ended March 31, 2019 and 2020, respectively. The change in tax rate is primarily due to the impact of stock compensation deductions for tax. The effective income tax rate reflects the effect of federal and state income taxes and the permanent impacts of differences in book and tax accounting. The Company’s effective tax rate for the three months ended March 31, 2019 and 2020 is higher than the U.S. federal statutory rate of 21.0% primarily due to the impact of stock compensation tax deductions. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security (CARES) Act (the “Act”) was enacted. This Act included multiple income tax provisions that impact the Company’s tax expense, such as relaxing limitations on the deductibility of interest and the use of net operating losses arising in taxable years beginning after December 31, 2017. The Company has accounted for the estimated impact of the Act.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2020
Related Party Transactions [Abstract]
Related Parties	15. Related Parties On April 20, 2015, the Company created a wholly owned subsidiary, Republic, which was incorporated in Delaware. On November 30, 2016, the Company completed a pro-rata distribution of the common stock of Republic to its stockholders of record as of the close of business (the “Spin-Off”). In connection with the Spin-Off on November 30, 2016, the Company and Republic entered into certain agreements in order to govern the ongoing relationships between the two companies after the Spin-Off and to provide for an orderly transition. The agreements include a Transition Services Agreement, Facilities Sharing Agreement, Tax Sharing Agreement, and Master Services Agreement. The equity holders of Bandwidth pre-initial public offering are comprised of substantially the same individuals and entities that are the equity owners of Republic. The Company has determined the equity owners of Republic are related parties of Bandwidth. The Company has certain involvement with Republic via ongoing services arrangements, with these ongoing services arrangements creating a variable interest in Republic. The Company assessed the relationship with Republic under guidance for variable interest entities (“VIE”). Because investors in Republic have disproportionate voting rights, the Company concluded that Republic is a VIE, but Bandwidth is not a primary beneficiary. The Company’s maximum exposure to loss relating to this VIE is limited to amounts due under the service agreements between the Company and Republic. For the three months ended March 31, 2019 and 2020, the Company recorded a reduction of rent expense under the Facilities Sharing Agreement of $251 and $96, respectively, which is included in general and administrative expenses in the condensed consolidated statements of operations. No amounts were due to the Company under the Facilities Sharing Agreement as of December 31, 2019 and March 31, 2020. The Tax Sharing Agreement governs rights and obligations after the Spin-Off regarding income taxes and other taxes, including tax liabilities and benefits, attributes, returns and contests. There were no amounts outstanding or payable under this agreement as of December 31, 2019 and March 31, 2020. The Master Services Agreement specifies certain wholesale telecommunications services to be provided by the Company. The agreement is cancellable at any time by either party. During the three months ended March 31, 2019 and 2020, the Company provided telecommunication services to Republic of $892 and $533, respectively. The Company recognized such amounts as revenue in the accompanying condensed consolidated statements of operations. As of December 31, 2019 and March 31, 2020, the Company had a receivable of $161 and $153, respectively, under the Master Services Agreement. On March 1, 2019, an amendment to the current Master Services Agreement was executed. Pursuant to the terms of the new agreement, Republic receives reduced pricing on its messaging services, effective April 1, 2019. All other terms and conditions of the existing agreement remain. On June 20, 2019, Republic executed a further amendment to the current Master Services Agreement. Pursuant to the terms of the June 20, 2019 amendment, Republic receives reduced pricing on its outbound voice services effective on June 20, 2019. Republic also executed a revenue commitment schedule on June 20, 2019. Pursuant to the revenue commitment schedule, Republic agreed to spend a minimum of $100 per month during the 11-month period commencing July 1, 2019 through May 31, 2020. Subsequent to the expiration of the 180-day IPO blackout window on May 9, 2018, Republic employees that held Bandwidth stock options began exercising their options. Upon exercise, Bandwidth withholds the employee tax amounts due from the proceeds. Bandwidth had collected on behalf of, and remitted withholding tax to, Republic of $613 and $308 for the three months ended March 31, 2019 and 2020, respectively. There were no amounts outstanding or payable as of December 31, 2019 and March 31, 2020. On September 30, 2019, the Company entered into a services agreement with Republic. Pursuant to the terms of the new agreement, Republic receives services performed by the Company’s legal department, effective September 30, 2019. The Company is compensated by Republic for these services based on costs incurred by the Company. The Company received net compensation under this agreement of $31 for the three months ended March 31, 2020, which is included in general and administrative expenses in the condensed consolidated statements of

Basic and Diluted Income (Loss)

Basic and Diluted Income (Loss) per Common Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Basic and Diluted Income (Loss) per Common Share	16. Basic and Diluted Income (Loss) per Common Share Basic net income (loss) per share is computed by dividing net income by the weighted-average number of shares of common stock outstanding during the period. Diluted net income (loss) per share is computed by giving effect to all potential shares of common stock, including stock options and stock related to unvested restricted stock awards. The components of basic and diluted income (loss) per share are as follows: Three months ended March 31, 2019 2020 Net income (loss) attributable to common stockholders $ 1,992 $ (1,058) Net income (loss) per share: Basic $ 0.10 $ (0.04) Diluted $ 0.09 $ (0.04) Weighted Average Number of Common Shares Outstanding Basic 20,498,104 23,563,569 Dilutive effect of stock options, restricted stock units, and warrants 1,477,840 — Diluted 21,975,944 23,563,569

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	17. Subsequent Event On April 7, 2020, the Council of State authorized the sale by the State of North Carolina (the “State”) to Bandwidth of approximately 40 acres of vacant land located at the southwest quadrant of Reedy Creek Road and Edwards Mill Road in Raleigh, North Carolina (the “Land”). The consideration for the proposed sale of the Land to Bandwidth is $30,000. If Bandwidth completes the acquisition of the Land, Bandwidth will construct, at Bandwidth’s expense, a parking lot and related improvements on land adjacent to the approximately 40 acres to be sold to Bandwidth that will be retained by the State. The purchase and sale of the Land, as well as the transactions described above, remain subject to the execution of definitive agreements and are subject to due diligence and other customary closing conditions.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company's Annual Report on Form 10-K filed with the SEC on February 21, 2020. The condensed consolidated balance sheet as of December 31, 2019, included herein, was derived from the audited financial statements as of that date, but does not include all disclosures, including certain notes required by GAAP on an annual reporting basis. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial position, results of operations, comprehensive income (loss) and cash flows for the interim periods, but are not necessarily indicative of the results of operations to be anticipated for the full year 2020 or any future period.
Reclassification	Reclassification The Company reclassified certain prior year amounts to conform to the current year presentation. These reclassifications had no impact on the previously reported total assets, liabilities, stockholder’s deficit or net income.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of Bandwidth Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the amounts reported in these financial statements and accompanying notes. These estimates in the condensed consolidated financial statements include, but are not limited to, allowance for doubtful accounts, reserve for sales credits, recoverability of long lived and intangible assets, discount rates used in the valuation of right-of-use assets and lease liabilities, the fair value of the liability and equity components of the Company’s Convertible Notes (as defined herein), estimated period of benefit, valuation allowances on deferred tax assets, certain accrued expenses, and contingencies. Although the Company believes that the estimates it uses are reasonable, due to the inherent uncertainty involved in making these estimates, actual results reported in future periods could differ from those estimates.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents The Company classifies all highly liquid investments with stated maturities of three months or less from the date of purchase as cash equivalents and all highly liquid investments with stated maturities of greater than three months from the date of purchase as current marketable securities. Cash deposits are primarily in financial institutions in the US. However, cash for monthly operating costs of international operations are deposited in banks outside the US. The Company has a policy of making investments only with commercial institutions that have at least an investment grade credit rating. The Company invests its cash primarily in government securities and obligations, corporate debt securities, money market funds and reverse repurchase agreements (“RRAs”). RRAs are collateralized by deposits in the form of Government Securities and Obligations for an amount not less than 102% of their value. The Company does not record an asset or liability as the Company is not permitted to sell or repledge the associated collateral. The Company has a policy that the collateral has at least an “A” (or equivalent) credit rating. The Company utilizes a third-party custodian to manage the exchange of funds and ensure that collateral received is maintained at 102% of the value of the RRAs on a daily basis. RRAs with stated maturities of greater than three months from the date of purchase are classified as marketable securities. Restricted Cash Restricted cash consists primarily of cash deposited into a savings account with a financial institution as collateral for the Company’s obligations under the Convertible Notes, as well as customer deposits, employee withholding tax liability and employee benefits contributions not yet remitted. The Company has classified this asset as a short-term asset in order to match the expected period of restriction. See Note 8, “Debt” to these condensed consolidated financial statements, for further information.
Accounts Receivable	Accounts Receivable and Current Expected Credit Losses Accounts receivable are stated at realizable value, net of an allowance for doubtful accounts, which includes a reserve for expected credit losses. The allowance for doubtful accounts is based on management’s assessment of the collectability of its customer accounts. The Company regularly reviews the composition of the accounts receivable aging, historical bad debts, changes in payment patterns, customer creditworthiness, current economic trends, and reasonable and supportable forecasts about the future. Relevant risks characteristics include customer size and historical loss patterns. Management has evaluated the expected credit losses related to trade accounts receivable and determined that allowances of approximately $769 and $883 for uncollectible accounts and customer balances that are disputed were required as of December 31, 2019 and March 31, 2020, respectively. Refer to Note 4, “Financial Statement Components” to these condensed consolidated financial statements, for a rollforward of the components of the allowance for doubtful accounts as of December 31, 2019 and March 31, 2020. Refer to the Recently Adopted Accounting Standard section for the adoption of ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses .
Current Expected Credit Losses	Accounts Receivable and Current Expected Credit Losses Accounts receivable are stated at realizable value, net of an allowance for doubtful accounts, which includes a reserve for expected credit losses. The allowance for doubtful accounts is based on management’s assessment of the collectability of its customer accounts. The Company regularly reviews the composition of the accounts receivable aging, historical bad debts, changes in payment patterns, customer creditworthiness, current economic trends, and reasonable and supportable forecasts about the future. Relevant risks characteristics include customer size and historical loss patterns. Management has evaluated the expected credit losses related to trade accounts receivable and determined that allowances of approximately $769 and $883 for uncollectible accounts and customer balances that are disputed were required as of December 31, 2019 and March 31, 2020, respectively. Refer to Note 4, “Financial Statement Components” to these condensed consolidated financial statements, for a rollforward of the components of the allowance for doubtful accounts as of December 31, 2019 and March 31, 2020. Refer to the Recently Adopted Accounting Standard section for the adoption of ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses .
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that are exposed to concentration of credit risk consist primarily of cash and cash equivalents, marketable securities and trade accounts receivable. Cash deposits may be in excess of insured limits. The Company believes that the financial institutions that hold its cash deposits are financially sound and, accordingly, minimal credit risk exists with respect to these balances.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ( “ ASU ” ) 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract . This standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 is effective for interim and annual reporting periods beginning after December 15, 2019. As a result of the Company ’ s prospective adoption of this standard, the Company capitalized i mplementation costs related to cloud computing arrangements of $272 as of March 31, 2020. See Note 6, “Property and Equipment” to these condensed consolidated financial statements, for additional details. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, which eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information and modifies some disclosure requirements. ASU 2018-13 is effective for interim and annual reporting periods beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of this standard did not have a material impact on the Company ’ s financial statements. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment , which simplifies the accounting for goodwill impairment. The ASU removes the second step of the goodwill impairment test that requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. ASU 2017-04 is effective for interim and annual reporting periods beginning after December 15, 2019. The adoption of this standard did not have a material impact on the Company’s financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments–Credit Losses: Measurement of Credit Losses on Financial Instruments , which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which will generally result in earlier recognition of allowances for losses. In November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses , which clarifies that receivables arising from operating leases are not within the scope of Topic 326, Financial Instruments – Credit Losses. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with Topic 842, Leases. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, which clarifies how to apply certain aspects of the new credit losses standard. In November 2019, the FASB issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates , which amends certain effective dates for the new standard. In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , which clarifies how to apply certain aspects of the new credit losses standard. The accounting standard is effective for annual and interim periods beginning after December 15, 2019. The Company adopted this standard for financial assets measured at amortized cost, including trade receivables. Results for the reporting periods beginning after January 1, 2020 are presented under ASC 326, while prior period amounts continue to be reported in accordance with previously applicable GAAP. The adoption of this standard did not have a material impact on the Company’s financial statements. Recent Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted, including adoption in an interim period. The Company is evaluating the effect of adopting this new accounting guidance, but does not expect adoption will have a material impact on its financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Schedule of Intangible Assets Useful Life	Intangible assets, net consisted of the following as of December 31, 2019: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,591) $ 5,805 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,524) $ 6,569 Intangible assets, net consisted of the following as of March 31, 2020: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,721) $ 5,675 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,654) $ 6,439

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on a Recurring Basis	The following table summarizes the assets measured at fair value as of December 31, 2019 and March 31, 2020: Fair value measurements on a recurring basis Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents: Money market account $ 25,000 $ — $ — $ 25,000 Time deposits 75,250 — — 75,250 Total financial assets $ 100,250 $ — $ — $ 100,250 Fair value measurements on a recurring basis Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents: Money market account $ 135,113 $ — $ — $ 135,113 Time deposits 255,515 — — 255,515 Total financial assets $ 390,628 $ — $ — $ 390,628

Financial Statement Components

Financial Statement Components (Tables)	3 Months Ended
	Mar. 31, 2020
Financial Statement Components [Abstract]
Schedule of Accounts Receivable, net, and Allowance for Doubtful Accounts	Accounts receivable, net of allowance for doubtful accounts consist of the following: As of December 31, As of March 31, 2019 2020 Trade accounts receivable $ 14,692 $ 16,553 Unbilled accounts receivable 16,200 20,788 Allowance for doubtful accounts (769) (883) Other accounts receivable 64 614 Total accounts receivable, net $ 30,187 $ 37,072 Components of allowance for doubtful accounts are as follows: Three months ended March 31, 2019 2020 Allowance for doubtful accounts: Balance, beginning of period $ (906) $ (769) Charged to bad debt expense (132) (189) Deductions (1) 20 75 Balance, end of period $ (1,018) $ (883) ________________________ (1) Write off of uncollectible accounts after all collection efforts have been exhausted.
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: As of December 31, As of March 31, 2019 2020 Accrued expense $ 12,701 $ 13,250 Accrued compensation and benefits 8,284 4,378 Accrued sales, use, and telecom related taxes 5,439 5,006 Other accrued expenses 904 1,147 Total accrued expenses and other current liabilities $ 27,328 $ 23,781

Right-of-Use Asset and Lease _2

Right-of-Use Asset and Lease Liabilities (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of Future Minimum Lease Receipts for Operating Lease	Future minimum sub-lease receipts required under the non-cancellable lease are as follows: As of March 31, 2020 2020 (remaining) $ 337 2021 457 2022 249 $ 1,043
Components of Lease Expense	The components of lease expense recorded in the condensed consolidated statement of operations were as follows: Three months ended March 31, 2019 2020 Operating lease cost $ 1,218 $ 1,461 Sublease income (1) (251) (96) Total net lease cost $ 967 $ 1,365 ________________________ (1) See Note 15, “Related Parties” to these condensed consolidated financial statements, for additional details on sublease income. Supplemental cash flow and other information related to leases was as follows: Three months ended March 31, 2019 2020 Cash paid for amounts included in the measurement of operating lease liabilities $ 938 $ 1,285 Weighted average remaining operating lease term (in years) 5.04 4.11 Weighted average operating lease discount rate 5.11 % 4.99 %
Supplemental Balance Sheet Information	Supplemental balance sheet information related to leases was as follows: As of December 31, As of March 31, Leases Classification 2019 2020 Assets: Operating lease assets Operating ROU asset, net of accumulated amortization (1) $ 21,031 $ 19,873 Total leased assets $ 21,031 $ 19,873 Liabilities: Current Operating Operating lease liability, current $ 4,876 $ 4,973 Non-current Operating Operating lease liability, non-current 19,868 18,486 Total lease liabilities $ 24,744 $ 23,459 ________________________ (1) Operating lease assets are recorded net of accumulated amortization of $4,269 and $5,427 as of December 31, 2019 and March 31, 2020, respectively.
Schedule of Maturities of Lease Liabilities	Maturities of operating lease liabilities were as follows: As of March 31, 2020 2020 (remaining) $ 4,319 2021 6,587 2022 6,302 2023 5,926 2024 1,987 2025 949 Total lease payments 26,070 Less: imputed interest (2,591) Less: accrued lease incentive (20) Total lease obligations 23,459 Less: current obligations (4,973) Long-term lease obligations $ 18,486

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following: As of December 31, As of March 31, 2019 2020 Furniture and fixtures $ 2,373 $ 2,387 Computer and office equipment 4,627 4,725 Telecommunications equipment 44,324 48,460 Leasehold improvements 5,263 5,853 Software 2,018 2,027 Internal-use software development 17,952 18,512 Automobile 10 10 Total cost 76,567 81,974 Less—accumulated depreciation (34,913) (38,069) Total property and equipment, net $ 41,654 $ 43,905
Schedule of Depreciation Expense	The Company recognized depreciation expense, which includes amortization of capitalized software development costs, as follows: Three months ended March 31, 2019 2020 Cost of revenue $ 1,293 $ 2,334 Research and development 69 115 Sales and marketing 28 29 General and administrative 689 690 Total depreciation expense $ 2,079 $ 3,168

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets, net consisted of the following as of December 31, 2019: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,591) $ 5,805 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,524) $ 6,569 Intangible assets, net consisted of the following as of March 31, 2020: Gross Accumulated Net Carrying Amortization (Years) Customer relationships $ 10,396 $ (4,721) $ 5,675 20 Other, definite lived 3,933 (3,933) — 2 - 7 Licenses, indefinite lived 764 — 764 Indefinite Total intangible assets, net $ 15,093 $ (8,654) $ 6,439
Schedule of Future Estimated Amortization Expense	Future estimated amortization expense for definite lived intangible assets is as follows: As of March 31, 2020 2020 (remaining) $ 390 2021 520 2022 520 2023 520 2024 520 Thereafter 3,205 $ 5,675

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Net Carrying Amount of Liability and Equity Component of Notes	The net carrying amount of the liability component of the Convertible Notes was as follows: As of March 31, 2020 Principal $ 400,000 Unamortized discount (123,531) Unamortized debt issuance costs (8,086) Net carrying amount $ 268,383 The net carrying amount of the equity component of the Convertible Notes was as follows: As of March 31, 2020 Proceeds allocated to the conversion options (debt discount) $ 125,160 Issuance costs (3,731) Net carrying amount $ 121,429
Interest Income and Interest Expense Disclosure	The following table sets forth the interest expense recognized related to the Convertible Notes: As of March 31, 2020 Contractual interest expense $ 96 Amortization of debt issuance costs 1,629 Amortization of debt discount 106 Total interest expense related to the Convertible Notes $ 1,831

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Three months ended March 31, 2019 2020 CPaaS Revenue $ 45,013 $ 59,121 Cost of revenue 25,300 31,892 Gross profit $ 19,713 $ 27,229 Other Revenue $ 8,308 $ 9,397 Cost of revenue 3,466 4,467 Gross profit $ 4,842 $ 4,930 Consolidated Revenue $ 53,321 $ 68,518 Cost of revenue 28,766 36,359 Gross profit $ 24,555 $ 32,159
Schedule of Revenue by Geographical Area	The Company generates its revenue primarily in the United States. Revenue by geographic area is detailed in the table below (which is determined based on the customer billing address): Three months ended March 31, 2019 2020 CPaaS United States $ 44,944 $ 57,398 International 69 1,723 Total $ 45,013 $ 59,121 Other United States $ 8,229 $ 9,125 International 79 272 Total $ 8,308 $ 9,397

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Schedule of Reserved Shares of Common Stock for Issuance	The Company had reserved shares of Class A common stock for issuance under stock-based award agreements as follows: As of December 31, As of March 31, 2019 2020 Stock options issued and outstanding 853,399 820,966 Nonvested restricted stock units issued and outstanding 392,351 494,009 Stock-based awards available for grant under the 2017 Plan 1,310,354 2,034,096 2,556,104 3,349,071

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following summarizes the stock option activity for the periods presented: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2019 853,399 $ 8.07 3.41 $ 47,770 Granted — — Exercised (32,059) 7.61 2,136 Forfeited or cancelled (374) 19.51 Outstanding as of March 31, 2020 820,966 $ 8.09 3.16 $ 48,604 Options vested and exercisable at March 31, 2020 731,316 $ 7.29 2.67 $ 43,879 Options vested and expected to vest as of March 31, 2020 820,106 $ 8.08 3.15 $ 48,559
Summary of Restricted Stock Unit Activity	The following summarizes the RSU activity for the periods presented: Number of awards outstanding Weighted-average grant date fair value (per share) Nonvested RSUs as of December 31, 2019 392,351 $ 35.22 Granted 208,441 64.16 Vested (103,824) 34.37 Forfeited or cancelled (2,959) 50.05 Nonvested RSUs as of March 31, 2020 494,009 $ 47.72
Schedule of Stock-Based Compensation Expense	The Company recognized total stock-based compensation expense as follows: Three months ended March 31, 2019 2020 Cost of revenue $ 56 $ 175 Research and development 372 453 Sales and marketing 320 395 General and administrative 928 1,476 Total $ 1,676 $ 2,499

Basic and Diluted Income per Co

Basic and Diluted Income per Common Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The components of basic and diluted income (loss) per share are as follows: Three months ended March 31, 2019 2020 Net income (loss) attributable to common stockholders $ 1,992 $ (1,058) Net income (loss) per share: Basic $ 0.10 $ (0.04) Diluted $ 0.09 $ (0.04) Weighted Average Number of Common Shares Outstanding Basic 20,498,104 23,563,569 Dilutive effect of stock options, restricted stock units, and warrants 1,477,840 — Diluted 21,975,944 23,563,569

Organization and Description _2

Organization and Description of Business (Details) - segment	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	2
Number of reportable segments	2	2

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Estimates and Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019
Change in Accounting Estimate [Line Items]
Revenue	$ 68,518	$ 53,321
Cost of revenue	$ 36,359	$ 28,766
RRAs collateralized by deposits in form of Government Securities and Obligations as percentage of value	102.00%
Estimated Period of Benefit for Nonrefundable Upfront Fees [Member]
Change in Accounting Estimate [Line Items]
Revenue	$ 439
Cost of revenue	$ 319
Estimated Period of Benefit for Nonrefundable Upfront Fees [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Change in Accounting Estimate [Line Items]
Revenue, remaining performance obligation, amount, expected timing of satisfaction, period			4 years	3 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Accounts Receivable and Current Expected Credit Losses and Concentration of Credit Risk (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Accounting Policies [Abstract]
Allowance for doubtful accounts	$ 883		$ 769
Unbilled accounts receivable	$ 20,788		$ 16,200
Customer One | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	0.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Recently Adopted Accounting Standards (Details) $ in Thousands	Mar. 31, 2020USD ($)
ASU 2018-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized implementation costs related to cloud computing arrangements	$ 272

Fair Value Measurements - Asset

Fair Value Measurements - Assets Measured at Fair Value (Details) - Fair value measurements on a recurring basis - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Money market account
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 135,113	$ 25,000
Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	255,515	75,250
Financial assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	390,628	100,250
Level 1 | Money market account
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	135,113	25,000
Level 1 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	255,515	75,250
Level 1 | Financial assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	390,628	100,250
Level 2 | Money market account
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 2 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 2 | Financial assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	0	0
Level 3 | Money market account
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Financial assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Maturities of marketable securities	$ 0	$ 9,000,000
Interest earned on marketable securities	0	$ 3,000
Convertible notes | 0.25% convertible senior notes due 2026
Debt Instrument [Line Items]
Fair value	$ 384,490,000

Financial Statement Component_2

Financial Statement Components - Accounts Receivable, Net of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financial Statement Components [Abstract]
Trade accounts receivable	$ 16,553	$ 14,692
Unbilled accounts receivable	20,788	16,200
Allowance for doubtful accounts	(883)	(769)
Other accounts receivable	614	64
Total accounts receivable, net	$ 37,072	$ 30,187

Financial Statement Component_3

Financial Statement Components - Allowance For Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of period	$ (769)	$ (906)
Balance, end of period	(883)	(1,018)
Accounts Receivable, Excluding Carrier Access Billing (CAB)
Allowance for Doubtful Accounts Receivable [Roll Forward]
Charged to bad debt expense	(189)	(132)
Deductions	$ 75	$ 20

Financial Statement Component_4

Financial Statement Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financial Statement Components [Abstract]
Accrued expense	$ 13,250	$ 12,701
Accrued compensation and benefits	4,378	8,284
Accrued sales, use, and telecom related taxes	5,006	5,439
Other accrued expenses	1,147	904
Total accrued expenses and other current liabilities	$ 23,781	$ 27,328

Right-of-Use Asset and Lease _3

Right-of-Use Asset and Lease Liabilities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020property	May 29, 2019ft²
Lessee, Lease, Description [Line Items]
Office space (in square foot) | ft²		17,073
Number of leased properties | property	6
Option to extend, term	5 years
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	2 years 3 months 29 days
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	5 years 5 months 1 day

Right-of-Use Asset and Lease _4

Right-of-Use Asset and Lease Liabilities - Future Minimum Sub-lease Receipts (Details) $ in Thousands	Mar. 31, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
2020 (remaining)	$ 337
2021	457
2022	249
Total	$ 1,043

Right-of-Use Asset and Lease _5

Right-of-Use Asset and Lease Liabilities - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating lease cost	$ 1,461	$ 1,218
Sublease income	(96)	(251)
Total net lease cost	$ 1,365	$ 967

Right-of-Use Asset and Lease _6

Right-of-Use Asset and Lease Liabilities - Assets And Liabilities, Lessee (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating right-of-use asset, net of accumulated amortization	$ 19,873	$ 21,031
Operating lease liability, current	4,973	4,876
Long-term lease obligations	18,486	19,868
Total lease liabilities	23,459	24,744
Accumulated amortization	$ 5,427	$ 4,269

Right-of-Use Asset and Lease _7

Right-of-Use Asset and Lease Liabilities - Supplemental Cash Flow and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 1,285	$ 938
Weighted average remaining operating lease term (in years)	4 years 1 month 9 days	5 years 14 days
Weighted average operating lease discount rate	4.99%	5.11%

Right-of-Use Asset and Lease _8

Right-of-Use Asset and Lease Liabilities - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2020 (remaining)	$ 4,319
2021	6,587
2022	6,302
2023	5,926
2024	1,987
2025	949
Total lease payments	26,070
Less: imputed interest	(2,591)
Less: accrued lease incentive	(20)
Total lease liabilities	23,459	$ 24,744
Less: current obligations	(4,973)	(4,876)
Long-term lease obligations	$ 18,486	$ 19,868

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total cost	$ 81,974	$ 76,567
Less—accumulated depreciation	(38,069)	(34,913)
Total property and equipment, net	43,905	41,654
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total cost	2,387	2,373
Computer and office equipment
Property, Plant and Equipment [Line Items]
Total cost	4,725	4,627
Telecommunications equipment
Property, Plant and Equipment [Line Items]
Total cost	48,460	44,324
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total cost	5,853	5,263
Software
Property, Plant and Equipment [Line Items]
Total cost	2,027	2,018
Internal-use software development
Property, Plant and Equipment [Line Items]
Total cost	18,512	17,952
Automobile
Property, Plant and Equipment [Line Items]
Total cost	$ 10	$ 10

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Capitalized software development costs, additions	$ 790	$ 595
Amortization of capitalized software development costs	582	$ 789
ASU 2018-15
Property, Plant and Equipment [Line Items]
Capitalized implementation costs related to cloud computing arrangements	272
Prepaid expenses and other current assets
Property, Plant and Equipment [Line Items]
Capitalized implementation costs related to cloud computing arrangements	58
Other long-term assets
Property, Plant and Equipment [Line Items]
Capitalized implementation costs related to cloud computing arrangements	$ 214

Property and Equipment - Deprec

Property and Equipment - Depreciation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Depreciation Expense [Line Items]
Total depreciation expense	$ 3,168	$ 2,079
Cost of revenue
Depreciation Expense [Line Items]
Total depreciation expense	2,334	1,293
Research and development
Depreciation Expense [Line Items]
Total depreciation expense	115	69
Sales and marketing
Depreciation Expense [Line Items]
Total depreciation expense	29	28
General and administrative
Depreciation Expense [Line Items]
Total depreciation expense	$ 690	$ 689

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (8,654)		$ (8,524)
Finite-lived intangible assets, net	5,675
Gross amount	15,093		15,093
Net carrying value	6,439		6,569
Licenses
Indefinite-lived Intangible Assets [Line Items]
Licenses, indefinite lived	764		764
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	10,396		10,396
Accumulated amortization	(4,721)		(4,591)
Finite-lived intangible assets, net	$ 5,675		5,805
Amortization period	20 years	20 years
Other, definite lived
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 3,933		3,933
Accumulated amortization	(3,933)		(3,933)
Finite-lived intangible assets, net	$ 0		$ 0
Other, definite lived | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period	2 years	2 years
Other, definite lived | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization period	7 years	7 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 130	$ 130
Weighted average amortization period	11 years

Intangible Assets - Future Esti

Intangible Assets - Future Estimated Amortization Expense (Details) $ in Thousands	Mar. 31, 2020USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2020 (remaining)	$ 390
2021	520
2022	520
2023	520
2024	520
Thereafter	3,205
Finite-lived intangible assets, net	$ 5,675

Debt - Additional Information (

Debt - Additional Information (Details)	Feb. 28, 2020USD ($)d$ / sharesshares	Mar. 31, 2020USD ($)$ / shares	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 107,000	$ 125,000
Debt outstanding		268,383,000
Principal		$ 400,000,000
Total net proceeds	$ 344,757,000
Conversion price (usd per share) | $ / shares	$ 91.03
Cash redemption price, percent	100.00%
Trading days | d	20
Consecutive trading days | d	30
Conversion option	$ 125,160,000
Effective interest rate	6.763%
Carrying amount of equity component	$ 57,502,000
Annual effective interest rate	6.805%
Net cost of capped call purchase	$ 43,320,000
Issuance costs attributable to the liability component	$ 8,192,000
Conversion option 1
Debt Instrument [Line Items]
Trading days | d	20
Consecutive trading days | d	30
Conversion option 2
Debt Instrument [Line Items]
Consecutive trading days | d	10
Consecutive business days | d	5
Common Class A
Debt Instrument [Line Items]
Conversion ratio	10.9857
Common stock, par value (in usd per share) | $ / shares		$ 0.001
Capped call shares (in shares) | shares	4,394,276
Common Class A | Conversion option 1
Debt Instrument [Line Items]
Stock price trigger percent	130.00%
Common Class A | Conversion option 2
Debt Instrument [Line Items]
Stock price trigger percent	98.00%
Convertible notes | 0.25% convertible senior notes due 2026
Debt Instrument [Line Items]
Principal	$ 400,000,000
Stated rate	0.25%
Convertible notes | Capped call portion of 0.25% convertible senior notes due 2026
Debt Instrument [Line Items]
Conversion price (usd per share) | $ / shares	$ 91.03
Convertible notes | Capped call portion of 0.25% convertible senior notes due 2026 | Maximum
Debt Instrument [Line Items]
Conversion price (usd per share) | $ / shares	$ 137.40
Revolving Credit Facility
Debt Instrument [Line Items]
Debt outstanding		$ 0	0
Available borrowing capacity		25,000,000
Prepaid Expenses and Other Current Assets
Debt Instrument [Line Items]
Unamortized debt issuance costs		64,000	70,000
Noncurrent assets
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 43,000	$ 55,000

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($)	Feb. 28, 2020	Mar. 31, 2020
Debt Disclosure [Abstract]
Principal		$ 400,000,000
Unamortized discount		(123,531,000)
Unamortized debt issuance costs		(8,086,000)
Net carrying amount		268,383,000
Proceeds allocated to the conversion options (debt discount)	$ 125,160,000
Issuance costs	$ (3,731,000)
Net carrying amount		$ 121,429,000

Debt - Interest Income and Inte

Debt - Interest Income and Interest Expense Disclosure (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Debt Disclosure [Abstract]
Contractual interest expense	$ 96
Amortization of debt discount and issuance costs	1,629
Amortization of debt discount	106
Total interest expense related to the Convertible Notes	$ 1,831

Segment and Geographic Inform_3

Segment and Geographic Information - Reconciliation of Segment Profit (Loss) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)segment	Mar. 31, 2019USD ($)segment
Segment Reporting [Abstract]
Number of reportable segments | segment	2	2
Segment Reporting Information [Line Items]
Revenue	$ 68,518	$ 53,321
Cost of revenue	36,359	28,766
Gross profit	32,159	24,555
CPaaS
Segment Reporting Information [Line Items]
Revenue	59,121	45,013
Cost of revenue	31,892	25,300
Gross profit	27,229	19,713
Other
Segment Reporting Information [Line Items]
Revenue	9,397	8,308
Cost of revenue	4,467	3,466
Gross profit	$ 4,930	$ 4,842

Segment and Geographic Inform_4

Segment and Geographic Information - Reconciliation of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 68,518	$ 53,321
Assets	665,276		$ 341,416
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	2,437		$ 2,924
CPaaS
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	59,121	45,013
CPaaS | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	57,398	44,944
CPaaS | International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,723	69
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	9,397	8,308
Other | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	9,125	8,229
Other | International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 272	$ 79

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock (Details) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)	0	0
Preferred A stock, shares outstanding (in shares)	0	0

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details)	Mar. 31, 2020vote$ / sharesshares	Dec. 31, 2019$ / sharesshares	Mar. 31, 2019shares
Common Class A
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	100,000,000		100,000,000
Common stock voting rights, votes per share | vote	1
Common stock, par value (in usd per share) | $ / shares	$ 0.001
Common stock, shares issued (in shares)	19,206,200	18,584,478
Common stock, shares outstanding (in shares)	19,206,200	18,584,478
Common Class B
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	20,000,000		20,000,000
Common stock voting rights, votes per share | vote	10
Common stock, par value (in usd per share) | $ / shares	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	4,427,151	4,927,401
Common stock, shares outstanding (in shares)	4,427,151	4,927,401

Stockholders' Equity - Reserved

Stockholders' Equity - Reserved Shares of Common Stock for Issuance (Details) - shares	Mar. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	3,349,071	2,556,104
StockOptionsIssuedandOutstandingMember
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	820,966	853,399
Restricted Stock Units (RSUs) [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	494,009	392,351
Share-based Payment Arrangement [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	2,034,096	1,310,354

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Jan. 01, 2018	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Nov. 09, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)			3,349,071		2,556,104
Estimated grant date fair value of options vested			$ 46	$ 57
Unrecognized cost for stock based compensation			410
Unrecognized compensation cost related to non-vested RSUs			$ 22,083
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized cost for stock based compensation, period for recognition (in years)			1 year 2 months 23 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)			494,009		392,351
Vesting percentage			25.00%
Share-based compensation arrangement, requisite service period			4 years
Unrecognized cost for stock based compensation, period for recognition (in years)			3 years 1 month 17 days
Restricted Stock Units (RSUs) | Non-employee Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			4 years
Restricted Stock Units (RSUs) | Non-employee Board of Directors | Year one vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
Restricted Stock Units (RSUs) | Non-employee Board of Directors | First quarter vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			12.50%
Restricted Stock Units (RSUs) | Non-employee Board of Directors | Second quarter vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			12.50%
Restricted Stock Units (RSUs) | Non-employee Board of Directors | Third quarter vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			12.50%
Restricted Stock Units (RSUs) | Non-employee Board of Directors | Forth quarter vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			12.50%
Restricted Stock Units (RSUs) | Non-employee Board of Directors | Year two, three and four vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)						1,050,000
Common stock reserved for future issuance, percent increase		5.00%
Increase in shares available for grant (in shares)	929,224
2017 Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			4 years
Contractual life (in years)			10 years

Stock Based Compensation - Stoc

Stock Based Compensation - Stock Option Activity (Details) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Number of options outstanding
Number of options outstanding, beginning balance (in shares)	853,399
Number of options, granted (in shares)	0
Number of options exercised (in shares)	(32,059)
Number of options, forfeited or cancelled (in shares)	(374)
Number of options outstanding, ending balance (in shares)	820,966	853,399
Options vested and exercisable (in shares)	731,316
Options vested and expected to vest (in shares)	820,106
Weighted- average exercise price (per share)
Weighted-average exercise price, beginning balance (in usd per share)	$ 8.07
Weighted-average exercise price, granted (in usd per share)	0
Weighted-average exercise price, exercised (in usd per share)	7.61
Weighted-average exercise price, forfeited or cancelled (in usd per share)	19.51
Weighted-average exercise price, ending balance (in usd per share)	8.09	$ 8.07
Weighted-average exercise price, options vested and exercisable (in usd per share)	7.29
Weighted average exercise price, options vested and expected to vest (in usd per share)	$ 8.08
Weighted-average remaining contract life, options outstanding (in years)	3 years 1 month 28 days		3 years 4 months 28 days
Weighted-average remaining contract life, options vested and exercisable (in years)	2 years 8 months 1 day
Weighted average remaining contract life, options vested and expected to vest	3 years 1 month 24 days
Aggregate intrinsic value, options outstanding	$ 48,604	$ 47,770
Aggregate intrinsic value, options exercised	2,136
Aggregate intrinsic value, options vested and exercisable	43,879
Aggregate intrinsic value, options vested and expected to vest	$ 48,559

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Number of awards outstanding
Number of nonvested RSUs outstanding, beginning balance (in shares) | shares	392,351
Number of nonvested RSUs, granted (in shares) | shares	208,441
Number of nonvested RSUs, vested (in shares) | shares	(103,824)
Number of nonvested RSUs, forfeited or cancelled (in shares) | shares	(2,959)
Number of nonvested RSUs outstanding, ending balance (in shares) | shares	494,009
Weighted-average grant date fair value (per share)
Weighted-average grant date fair value, beginning balance (in usd per share) | $ / shares	$ 35.22
Weighted average grant-date fair value of nonvested RSUs, granted (in usd per share) | $ / shares	64.16
Weighted-average grant date fair value of nonvested RSUs, vested (in usd per share) | $ / shares	34.37
Weighted-average grant date fair value of nonvested restricted RSUs, forfeited or cancelled (in usd per share) | $ / shares	50.05
Weighted-average grant date fair value, ending balance (in usd per share) | $ / shares	$ 47.72

Stock Based Compensation - St_2

Stock Based Compensation - Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,499	$ 1,676
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	175	56
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	453	372
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	395	320
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,476	$ 928

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	Oct. 25, 2015	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Service agreement, annual minimum commitments	$ 1,200
Service agreement, term of agreement (in years)	5 years
Non-cancellable purchase obligation		$ 9,720
Non-cancellable purchase obligation, fulfilled within a year		$ 5,404
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term		5 years 5 months 1 day

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Retirement Benefits [Abstract]
Matching contributions	$ 634	$ 513

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	72.10%	135.20%

Related Parties (Details)

Related Parties (Details) - USD ($)	Jun. 20, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Rental payments received		$ 96,000	$ 251,000
Affiliated Entity | Republic
Related Party Transaction [Line Items]
Amount collected on behalf		308,000	613,000
Affiliated Entity | Republic | Facilities Sharing Agreement
Related Party Transaction [Line Items]
Rental payments received		96,000	251,000
Due from related parties		0		$ 0
Affiliated Entity | Republic | Tax Sharing Agreement
Related Party Transaction [Line Items]
Due from related parties		0		0
Affiliated Entity | Republic | Master Services Agreement
Related Party Transaction [Line Items]
Revenue from related parties		533,000	$ 892,000
Accounts receivable, related parties		153,000		161,000
Minimum monthly revenue expected from related party	$ 100,000
Minimum monthly revenue expected from related party, period	11 months
Affiliated Entity | Republic | Services Agreement
Related Party Transaction [Line Items]
Revenue from related parties		31,000
Accounts receivable, related parties		$ 10,000		$ 10,000

Basic and Diluted Income (Los_2

Basic and Diluted Income (Loss) per Common Share - Components of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net income (loss) attributable to common stockholders	$ (1,058)	$ 1,992
Net income (loss) per share:
Basic (in usd per share)	$ (0.04)	$ 0.10
Diluted (in usd per share)	$ (0.04)	$ 0.09
Weighted Average Number of Common Shares Outstanding
Basic (in shares)	23,563,569	20,498,104
Dilutive effect of stock options, restricted stock units, and warrants (in shares)	0	1,477,840
Diluted (in shares)	23,563,569	21,975,944

Basic and Diluted Income (Los_3

Basic and Diluted Income (Loss) per Common Share - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020shares
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of weighted-average common shares outstanding (in shares)	820,966
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of weighted-average common shares outstanding (in shares)	494,009

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event $ in Millions	Apr. 27, 2020	Apr. 07, 2020USD ($)a
Subsequent Event [Line Items]
Mimimum maturity	5 years
Authorized
Subsequent Event [Line Items]
Land (acres) | a		40
Consideration for the proposed Land purchase | $		$ 30

Uncategorized Items - band-2020

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (174,000)
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (174,000)