A10 Networks (ATEN) 10-Q 30 Apr 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 28, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-36343
Entity Registrant Name	A10 NETWORKS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-1446869
Entity Address, Address Line One	2300 Orchard Parkway
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95131
City Area Code	408
Local Phone Number	325-8668
Title of 12(b) Security	Common Stock, $0.00001 par value
Trading Symbol	ATEN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		77,335,510
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001580808
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 75,696	$ 83,281
Marketable securities	85,261	74,851
Accounts receivable, net of allowances of $4 and $41, respectively	51,449	51,051
Inventory	19,547	20,730
Prepaid expenses and other current assets	13,022	12,390
Total current assets	244,975	242,303
Property and equipment, net	8,223	7,888
Goodwill	1,307	1,307
Intangible assets, net	502	862
Other non-current assets	36,573	38,451
Total assets	291,580	290,811
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	4,521	4,851
Accrued liabilities	26,198	36,930
Deferred revenue	68,299	65,999
Total current liabilities	99,018	107,780
Deferred revenue, non-current	44,920	42,700
Other non-current liabilities	22,983	24,357
Total liabilities	166,921	174,837
Commitments and contingencies (Note 2 and Note 5)
Stockholders' equity:
Common stock, $0.00001 par value: 500,000 shares authorized; 77,102 and 76,346 shares issued and outstanding, respectively	1	1
Treasury stock, at cost: 5,587 and 5,578 shares, respectively	(37,498)	(37,410)
Additional paid-in-capital	431,738	425,534
Accumulated other comprehensive income	10	98
Accumulated deficit	(269,592)	(272,249)
Total stockholders' equity	124,659	115,974
Total liabilities and stockholders' equity	$ 291,580	$ 290,811

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 4	$ 41
Common Stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	77,102,000	76,346,000
Common stock, shares outstanding (in shares)	77,102,000	76,346,000
Treasury Stock, Shares	5,587,000	5,578,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Total revenue	$ 54,843	$ 53,764
Cost of revenue:
Total cost of revenue	12,499	12,142
Gross profit	42,344	41,622
Operating expenses:
Sales and marketing	19,092	20,621
Research and development	13,981	15,315
General and administrative	5,247	5,895
Total operating expenses	38,320	41,831
Income (loss) from operations	4,024	(209)
Non-operating income (expense):
Interest and other income (expense), net	(1,183)	231
Total non-operating income (expense), net	(1,183)	231
Income before provision for income taxes	2,841	22
Provision for income taxes	184	319
Net income (loss)	$ 2,657	$ (297)
Net income (loss) per share:
Basic	$ 0.03	$ 0
Diluted	$ 0.03	$ 0
Weighted-average shares used in computing net income (loss) per share:
Basic	76,704	78,061
Diluted	79,636	78,061
Products
Revenue:
Total revenue	$ 30,540	$ 30,736
Cost of revenue:
Total cost of revenue	7,086	6,941
Services
Revenue:
Total revenue	24,303	23,028
Cost of revenue:
Total cost of revenue	$ 5,413	$ 5,201

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,657	$ (297)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on marketable securities	(88)	(288)
Comprehensive income (loss)	$ 2,569	$ (585)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock
Beginning balance at Dec. 31, 2019	$ 108,787	$ 1	$ 403,470	$ 251	$ (290,065)	$ (4,870)
Beginning balance (in shares) at Dec. 31, 2019		77,580
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee equity incentive plans (in shares)		1,130
Common stock issued under employee equity incentive plans	0		2,005
Unrealized gain (loss) on marketable securities	(288)			(288)
Net income (loss)	(297)				(297)
Ending balance (in shares) at Mar. 31, 2020		78,710
Ending balance at Mar. 31, 2020	113,252	$ 1	408,520	(37)	(290,362)	$ (4,870)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition			3,045
Stock Repurchased During Period, Value	$ 0
Treasury Stock, Shares, Acquired						0
Common stock, shares outstanding (in shares)	76,346
Beginning balance at Dec. 31, 2020	$ 115,974	$ 1	425,534	98	(272,249)	$ (37,410)
Beginning balance (in shares) at Dec. 31, 2020		76,346
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee equity incentive plans (in shares)		756
Common stock issued under employee equity incentive plans	0		1,756
Unrealized gain (loss) on marketable securities	(88)			(88)
Net income (loss)	2,657				2,657
Ending balance (in shares) at Mar. 31, 2021		77,102
Ending balance at Mar. 31, 2021	124,659	$ 1	431,738	$ 10	$ (269,592)	$ (37,498)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition			$ 4,448
Stock Repurchased During Period, Value	$ (88)
Treasury Stock, Shares, Acquired	(10)					0
Common stock, shares outstanding (in shares)	77,102

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income (loss)	$ 2,657	$ (297)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	2,413	3,311
Stock-based compensation	4,399	3,040
Other non-cash items	181	(13)
Changes in operating assets and liabilities:
Accounts receivable	(315)	10,767
Inventory	1,086	1,472
Prepaid expenses and other assets	(60)	2,426
Accounts payable	(501)	(3,718)
Accrued and other liabilities	(12,106)	(4,919)
Deferred revenue	4,519	114
Net cash provided by operating activities	2,273	12,183
Cash flows from investing activities:
Proceeds from sales of marketable securities	1,300	1,914
Proceeds from maturities of marketable securities	24,140	10,175
Purchases of marketable securities	(36,197)	(5,518)
Purchases of property and equipment	(769)	(868)
Net cash provided by (used in) investing activities	(11,526)	5,703
Cash flows from financing activities:
Proceeds from issuance of common stock under employee equity incentive plans	1,756	2,005
Repurchase of common stock	(88)	0
Net cash provided by financing activities	1,668	2,005
Net increase (decrease) in cash and cash equivalents	(7,585)	19,891
Cash and cash equivalents—beginning of period	83,281	45,742
Cash and cash equivalents—end of period	75,696	65,633
Non-cash investing and financing activities:
Inventory transfers to property and equipment	97	149
Purchases of property and equipment included in accounts payable	$ 172	$ 63

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Description of Business A10 Networks, Inc. (together with our subsidiaries, the “Company”, “we”, “our” or “us”) was incorporated in California in 2004 and reincorporated in Delaware in March 2014. We are headquartered in San Jose, California and have wholly-owned subsidiaries throughout the world including Asia and Europe. We are a leading provider of networking solutions that enable next-generation networks focused on reliability, availability, scalability and cybersecurity. Our portfolio supports customers operating in the cloud, on-premise or in hybrid environments providing rapid return on their investment as well as investment protection with best-in-class technical performance. As cyber-attacks increase in volume and complexity, we integrate security as a key attribute in our solutions that further enable our customers to continue to adapt to market trends in cloud, internet of things and the ever increasing need for more data, building upon our strong global footprint and leadership in application and network infrastructure. Our customers include leading service providers (cloud, telecommunications, multiple system operators, cable), government organizations, and enterprises. Our product portfolio seeks to address many of the cyber protection challenges and solution requirements. The portfolio consists of six secure application solutions; Thunder Application Delivery Controller (“ADC”), Lightning Application Delivery Controller (“Lightning ADC”), Thunder Carrier Grade Networking (“CGN”), Thunder Threat Protection System (“TPS”), Thunder SSL Insight (“SSLi”) and Thunder Convergent Firewall (“CFW”) and intelligent management, and automation tools; Harmony Controller and aGalaxy TPS. Our products are offered in a variety of form factors and payment models, including physical appliances and perpetual and subscription-based software licenses, as well as pay-as-you-go licensing models and FlexPool, a flexible consumption-based software model. We derive revenue from sales of products and related support services. Products revenue is generated primarily by sales of hardware appliances with perpetual licenses to our embedded software solutions. We also derive revenue from licenses to, or subscription services for, software-only versions of our solutions. We generate services revenue primarily from sales of maintenance and support contracts. Our customers predominantly purchase maintenance and support in conjunction with purchases of our products. In addition, we also derive revenue from the sale of professional services. We sell our products globally to service providers and enterprises that depend on data center applications and networks to generate revenue and manage operations efficiently. We report two customer verticals: service providers and enterprises and we report customer revenues in four geographic regions: the Americas, Japan, Asia Pacific (excluding Japan) and EMEA. We believe this vertical and geographic view aligns with how we manage the business and maps our product portfolio to customer verticals. Our end-customers operate in a variety of industries, including telecommunications, technology, industrial, retail, financial, gaming, education and government. Since inception, our customer base has grown rapidly. As of March 31, 2021, we had sold products to more than 7,400 end-customers worldwide. We sell substantially all of our solutions through our high-touch sales organization as well as distribution channel partners, including distributors, value-added resellers and system integrators, and fulfill nearly all orders globally through such partners. We believe this sales approach allows us to obtain the benefits of channel distribution, such as expanding our market coverage, while still maintaining face-to-face relationships with our end-customers. We outsource the manufacturing of our hardware products to original design manufacturers. We perform quality assurance and testing at our San Jose, Taiwan and Japan distribution centers, as well as at our manufacturers’ locations. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include those of A10 Networks, Inc. and its subsidiaries after elimination of all intercompany accounts and transactions. We have prepared the accompanying unaudited condensed consolidated financial statements pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC” or the “Commission”). As permitted under these rules and regulations, we have condensed or omitted certain financial information and footnote disclosures we normally include in our annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The unaudited condensed consolidated balance sheet as of December 31, 2020 has been derived from our audited financial statements, which are included in our 2020 Annual Report on Form 10-K for the year ended December 31, 2020 on file with the SEC (the “2020 Annual Report”). These financial statements have been prepared on the same basis as our annual financial statements and, in management’s opinion, reflect all adjustments consisting only of normal recurring adjustments that are necessary for a fair presentation of our financial information. Our interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. The beginning and ending balances for treasury stock, at cost, have been reclassified from additional paid-in capital in the condensed consolidated statement of stockholders’ equity for the three months ended March 31, 2020 to conform with the current year presentation for treasury stock, at cost and additional paid-in capital. This reclassification did not have a material impact on the previously reported financial statements. These financial statements and accompanying notes should be read in conjunction with the financial statements and accompanying notes thereto in the 2020 Annual Report. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Those estimates and assumptions affect revenue recognition and deferred revenue, the allowance for doubtful accounts, the sales return reserve, the valuation of inventory, the fair value of marketable securities, contingencies and litigation, accrued liabilities, deferred commissions and the determination of fair value of stock-based compensation. These estimates are based on information available as of the date of the condensed consolidated financial statements. Due to the COVID-19 pandemic, there has been uncertainty and disruption in the global economy and financial markets. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of April 30, 2021, the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change, as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. Significant Accounting Policies The Company’s significant accounting policies are disclosed in Part II-Item 8, “Financial Statements and Supplementary Data,” of the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 8, 2021. There have been no material changes to the Company’s significant accounting policies during the three months ended March 31, 2021. Concentration of Credit Risk and Significant Customers Financial instruments that potentially subject us to concentrations of credit risk consist of cash, cash equivalents, marketable securities and accounts receivable. Our cash, cash equivalents and marketable securities are held and invested in high-credit quality financial instruments by recognized financial institutions and are subject to minimum credit risk. Our accounts receivable are unsecured and represent amounts due to us based on contractual obligations of our customers. We mitigate credit risk in respect to accounts receivable by performing periodic credit evaluations based on a number of factors, including past transaction experience, evaluation of credit history and review of the invoicing terms of the contract. We generally do not require our customers to provide collateral to support accounts receivable. Significant customers, including distribution channel partners and direct customers, are those which represent 10% or more of our total revenue for each period presented or our gross accounts receivable balance as of each respective balance sheet date. Revenues from our significant customers as a percentage of our total revenue are as follows: Three Months Ended March 31, Customers 2021 2020 Customer A (a distribution channel partner) 12% * Customer B (a distribution channel partner) 10% * Customer C (a distribution channel partner) * 17% Customer D (a distribution channel partner) * 16% * represents less than 10% of total revenue As of March 31, 2021, two customers accounted for 14% and 12%, respectively, of our total gross accounts receivable. As of December 31, 2020, two customers accounted for 17% and 10%, respectively, of our total gross accounts receivable. Recently Adopted Accounting Pronouncements Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), as amended, using a modified retrospective approach, with certain exceptions allowed. The standard amends the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the incurred-loss model with an expected-loss model. This new standard also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than by reducing the carrying amount under the current, other-than-temporary-impairment model. The adoption of ASU 2016-13 did not have a significant impact on the Company’s condensed consolidated financial statements. In January 2017, the Financial Accounting Standards Board (“FASB”) issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350)—Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating the requirement to compare the implied fair value of goodwill with its carrying amount as part of step two of the goodwill impairment test referenced in Accounting Standards Codification (“ASC”) 350, Intangibles - Goodwill and Other (“ASC 350”). As a result, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. However, the impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. In January 2020, the Company adopted ASU 2017-04, and the adoption did not have a material impact on the Company’s condensed consolidated financial statements. Effective January 1, 2020, the Company adopted ASU No. 2018-13, Fair Value Measurement (Topic 820 - Changes to the Disclosure Requirements for the Fair Value Measurement) (“ASU 2018-13”). Under ASU 2018-13, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. The guidance is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of ASU 2018-13 did not have a significant impact on the Company’s condensed consolidated financial statements. In November 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The amendments in this update improve consistent application of and simplify U.S. GAAP for Topic 740 by clarifying and amending existing guidance for, among other items, intra-period allocation, reporting tax law changes and losses in interim periods, state and local taxes not fully based on income and recognition of deferred tax liability related to certain transactions. There is also new guidance related to consolidated group reporting and tax impacts resulting from business combinations. The guidance is effective for public entities for fiscal years beginning after December 15, 2020 and for interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2021 and the adoption of this guidance did not have a significant impact on the Company’s condensed consolidated financial statements. In October 2020, the FASB issued ASU No. 2020-10, Codification Improvements . The amendments in this ASU improve the consistency of the codification and reorganize the guidance into appropriate sections providing less opportunities for disclosures to be missed. The amendments in this update do not change GAAP and are not expected to result in a significant change in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2020. Early

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	Leases The Company leases various operating spaces in the United States, Asia and Europe under non-cancellable operating lease arrangements that expire on various dates through July 2027. These arrangements require us to pay certain operating expenses, such as taxes, repairs and insurance, and contain renewal and escalation clauses. The table below presents the Company’s right-of-use assets and lease liabilities as of March 31, 2021 (in thousands): March 31, 2021 Operating leases Right-of-use assets: Other non-current assets $ 26,936 Total right-of-use assets $ 26,936 Lease liabilities: Accrued liabilities $ 5,181 Other non-current liabilities 22,197 Total operating lease liabilities $ 27,378 The aggregate future lease payments for non-cancelable operating leases as of March 31, 2021 were as follows (in thousands): Remainder of 2021 $ 4,494 2022 4,817 2023 4,414 2024 4,518 2025 4,625 Thereafter 7,148 Total lease payments 30,016 Less: imputed interest (2,638) Present value of lease liabilities $ 27,378 The components of lease costs were as follows (in thousands): Three Months Ended March 31, 2021 2020 Operating lease costs $ 1,373 $ 1,777 Short-term lease costs 147 158 Total lease costs $ 1,520 $ 1,935 Average lease terms and discount rates for the Company’s operating leases were as follows: March 31, 2021 Weighted-average remaining term (years) 5.98 Weighted-average discount rate 3.15% Supplemental cash flow information for the Company’s operating leases were as follows (in thousands): Three Months Ended March 31, 2021 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 1,500 No new operating leases were entered into during the three months ended March 31, 2021.

Marketable Securities and Fair

Marketable Securities and Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Marketable Securities and Fair Value Measurements	Marketable Securities and Fair Value Measurements Marketable Securities Marketable securities, classified as available-for-sale, consisted of the following (in thousands): March 31, 2021 December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ — $ — $ — $ — $ 2,150 $ — $ — $ 2,150 Corporate securities 50,477 22 (24) 50,475 45,070 83 (8) 45,145 U.S. Treasury and agency securities 9,496 9 — 9,505 9,493 12 — 9,505 Commercial paper 17,383 — — 17,383 12,136 — — 12,136 Asset-backed securities 7,895 3 — 7,898 5,904 11 — 5,915 Total $ 85,251 $ 34 $ (24) $ 85,261 $ 74,753 $ 106 $ (8) $ 74,851 During the three months ended March 31, 2021 and 2020, we did not reclassify any amount to earnings from accumulated other comprehensive income (loss) related to unrealized gains or losses. The following table summarizes the cost and estimated fair value of marketable securities based on stated effective maturities as of March 31, 2021 (in thousands): Amortized Cost Fair Value Less than 1 year $ 76,871 $ 76,887 Mature in 1 - 3 years 8,380 8,374 Total $ 85,251 $ 85,261 All available-for-sale securities have been classified as current because they are available for use in current operations. Marketable securities in an unrealized loss position as of March 31, 2021 consisted of the following (in thousands): Less Than 12 Months 12 Months or More Total As of March 31, 2021 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate securities $ 31,863 $ (18) $ 8,096 $ (6) $ 39,959 $ (24) Marketable securities in an unrealized loss position as of December 31, 2020 consisted of the following (in thousands): Less Than 12 Months 12 Months or More Total As of December 31, 2020 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate securities $ 20,355 $ (8) $ — $ — $ 20,355 $ (8) Based on evaluation of securities that have been in a continuous loss position, we did not recognize any other-than-temporary impairment charges during the three months ended March 31, 2021 and 2020. Fair Value Measurements The following is a summary of our cash, cash equivalents and marketable securities measured at fair value on a recurring basis (in thousands): March 31, 2021 December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Cash $ 60,138 $ — $ — $ 60,138 $ 62,388 $ — $ — $ 62,388 Cash equivalents 15,558 — — 15,558 20,893 — — 20,893 Certificates of deposit — — — — — 2,150 — 2,150 Corporate securities — 50,475 — 50,475 — 45,145 — 45,145 U.S. Treasury and agency securities — 9,505 — 9,505 — 9,505 — 9,505 Commercial paper — 17,383 — 17,383 — 12,136 — 12,136 Asset-backed securities — 7,898 — 7,898 — 5,915 — 5,915 Total $ 75,696 $ 85,261 $ — $ 160,957 $ 83,281 $ 74,851 $ — $ 158,132 There were no transfers between Level 1 and Level 2 fair value measurement categories during the three months ended March 31, 2021 and 2020.

Condensed Consolidated Financia

Condensed Consolidated Financial Statement Details	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Condensed Consolidated Financial Statement Details	Condensed Consolidated Financial Statement Details Inventory Inventory consisted of the following (in thousands): March 31, December 31, Raw materials $ 8,943 $ 8,395 Finished goods 10,604 12,335 Total inventory $ 19,547 $ 20,730 Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): March 31, December 31, Prepaid expenses $ 4,283 $ 3,818 Deferred contract acquisition costs 5,848 5,345 Other 2,891 3,227 Total prepaid expenses and other current assets $ 13,022 $ 12,390 Property and Equipment, Net Property and equipment, net, consisted of the following (in thousands): Useful Life March 31, December 31, (in years) Equipment 1 - 5 $ 25,875 $ 25,286 Software 1 - 3 765 765 Furniture and fixtures 1 - 7 652 652 Leasehold improvements Lease term 3,616 3,616 Construction in process 2,174 1,677 Property and equipment, gross 33,082 31,996 Less: accumulated depreciation (24,859) (24,108) Property and equipment, net $ 8,223 $ 7,888 Depreciation expense on property and equipment was $0.7 million and $1.3 million for the three months ended March 31, 2021 and 2020, respectively. Intangible Assets Purchased intangible assets, net, consisted of the following (in thousands): March 31, 2021 December 31, 2020 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Developed technology $ 5,050 $ (4,797) $ 253 $ 5,050 $ (4,545) $ 505 Patents 2,936 (2,687) 249 2,936 (2,579) 357 Total intangible assets $ 7,986 $ (7,484) $ 502 $ 7,986 $ (7,124) $ 862 Amortization expense related to purchased intangible assets was $0.4 million and $0.4 million for the three months ended March 31, 2021 and 2020, respectively. Future amortization expense for purchased intangible assets as of March 31, 2021 is as follows (in thousands): Fiscal Year Remainder of 2021 $ 502 Accrued Liabilities Accrued liabilities consisted of the following (in thousands): March 31, December 31, Accrued compensation and benefits $ 11,458 $ 19,725 Accrued tax liabilities 2,030 3,748 Lease liability 5,181 5,260 Other 7,529 8,197 Total accrued liabilities $ 26,198 $ 36,930 Deferred Revenue Deferred revenue consisted of the following (in thousands): March 31, December 31, Deferred revenue: Products $ 6,248 $ 7,358 Services 106,971 101,341 Total deferred revenue 113,219 108,699 Less: current portion (68,299) (65,999) Non-current portion $ 44,920 $ 42,700

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments We lease various operating spaces in the United States, Asia and Europe under non-cancelable operating lease arrangements that expire on various dates through July 2027. These arrangements require us to pay certain operating expenses, such as taxes, repairs and insurance, and contain renewal and escalation clauses. We recognize rent expense under these arrangements on a straight-line basis over the term of the lease. See Note 2 - Leases for the Company’s aggregate future lease payments for the Company’s non-cancelable operating leases as of March 31, 2021. Rent expense was $1.4 million and $1.6 million for three months ended March 31, 2021 and 2020, respectively. Purchase Commitments We have open purchase commitments with third-party contract manufacturers with facilities in Taiwan to supply nearly all of our finished goods inventories, spare parts, and accessories. These purchase orders are expected to be paid within one year of the issuance date. Guarantees and Indemnifications In the normal course of business, we provide indemnifications to customers against claims of intellectual property infringement made by third parties arising from the use of our products. Other guarantees or indemnification arrangements include guarantees of product and service performance, and standby letters of credit for lease facilities and corporate credit cards. We have not recorded a liability related to these indemnification and guarantee provisions and our guarantees and indemnification arrangements have not had any significant impact on our condensed consolidated financial statements to date.

Equity Incentive Plans and Stoc

Equity Incentive Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Equity Incentive Plans and Stock-Based Compensation	Equity Incentive Plans, Stock-Based Compensation and Stock Repurchase Program Equity Incentive Plans 2014 Equity Incentive Plan The 2014 Equity Incentive Plan (the “2014 Plan”) provides for the granting of stock options, restricted stock awards, restricted stock units (“RSUs”), performance-based RSUs (“PSUs”), stock appreciation rights, performance units and performance shares to our employees, consultants and members of our Board of Directors. The shares authorized for the 2014 Plan increase annually by the lesser of (i) 8,000,000 shares, (ii) 5% of the outstanding shares of common stock on the last day of our immediately preceding fiscal year, or (iii) such other lesser amount as determined by our Board of Directors. In November 2020, our Board of Directors determined the current shares authorized under the 2014 Plan were sufficient for the time being and decided not to increase the number of shares authorized in 2021. As of March 31, 2021, we had 10,537,636 shares available for future grant under the 2014 Plan. 2014 Employee Stock Purchase Plan In October 2018, the Board of Directors approved amending the 2014 Employee Stock Purchase Plan (the “Amended 2014 Purchase Plan”) in order to, among other things, reduce the maximum contribution participants can make under the plan from 15% to 10% of eligible compensation. The Amended 2014 Purchase Plan also reflects revised offering periods, which were changed from 24 months to six months in duration and that begin on or about December 1 and June 1 each year, starting in December 2018. As of March 31, 2021, the Company had 1,821,186 shares available for future issuance under the Amended 2014 Purchase Plan. Stock-Based Compensation A summary of our stock-based compensation expense is as follows (in thousands): Three Months Ended March 31, 2021 2020 Stock-based compensation by type of award: Stock options $ — $ 110 Stock awards 4,123 2,682 Employee stock purchase rights 276 248 $ 4,399 $ 3,040 Stock-based compensation by category of expense: Cost of revenue $ 572 $ 325 Sales and marketing 1,264 764 Research and development 1,431 1,006 General and administrative 1,132 945 $ 4,399 $ 3,040 As of March 31, 2021, the Company had $23.7 million of unrecognized stock-based compensation expense related to unvested stock-based awards which will be recognized over a weighted-average period of 2.39 years. Stock Options The following table summarizes our stock option activities and related information: Number of Shares (thousands) Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (thousands) Outstanding as of December 31, 2020 1,673 $ 5.44 Granted — — Exercised (338) 5.19 Canceled — — Outstanding as of March 31, 2021 1,335 5.51 2.70 $ 5,617 Vested and exercisable as of March 31, 2021 1,335 $ 5.51 2.70 $ 5,617 As of March 31, 2021, the aggregate intrinsic value represents the excess of the closing price of our common stock of $9.61 over the exercise price of the outstanding in-the-money options. The intrinsic value of options exercised was $1.5 million and $1.2 million during the three months ended March 31, 2021 and 2020, respectively. Stock Awards The Company has granted RSUs to its employees, consultants and members of its Board of Directors, and PSUs to certain executives and employees. The Company’s PSUs have market performance-based vesting conditions as well as service-based vesting conditions. As of March 31, 2021, there were 3,444,533 RSUs and 1,203,286 PSUs outstanding. The following table summarizes our stock award activities and related information: Number of Shares (thousands) Weighted-Average Grant Date Fair Value Per Share Weighted-Average Remaining Vesting Term Aggregate Fair Value (thousands) Nonvested as of December 31, 2020 4,888 $ 6.59 Granted 564 9.27 Released (428) 6.67 Canceled (376) 6.57 Nonvested as of March 31, 2021 4,648 $ 6.91 1.74 $ 44,666 The aggregate fair value of stock awards released was $4.0 million and $3.4 million for the three months ended March 31, 2021 and 2020, respectively. Stock Repurchase Program On September 17, 2020, the Company’s Board of Directors approved a stock repurchase program of up to $50 million of its common stock over a period of twelve months. During the three months ended March 31, 2021, the Company repurchased 10 thousand shares for a total cost of $88 thousand. Since approving the program, the Company has repurchased 2.7 million shares for a total cost of $19.3 million through March 31, 2021 and the Company had $30.7 million available to repurchase shares under this program as of March 31, 2021. Under the program, repurchased shares are held in treasury at cost. The Company’s stock repurchase program does not obligate us to acquire any specific number of shares. Shares may be repurchased in privately negotiated and/or open market transactions. To date, all repurchases under this program have occurred in the open market.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	Net Income (Loss) Per Share Basic net income (loss) per share is computed using the weighted average number of common shares outstanding for the period. Diluted net income (loss) per share applying the treasury stock method is computed using the weighted average number of common shares outstanding for the period plus potential dilutive common shares, including stock options, RSUs and employee stock purchase rights, unless the potential common shares are anti-dilutive. Since we had a net loss during the three months ended March 31, 2020, none of the potential dilutive common shares were included in the computation of diluted shares for this period, as inclusion of such shares would have been anti-dilutive. Basic and diluted net income (loss) per share are calculated as follows (in thousands, except per share amounts): Three Months Ended March 31, 2021 2020 Basic and diluted net income (loss) per share Numerator: Net income (loss) $ 2,657 $ (297) Denominator: Weighted-average shares outstanding - basic 76,704 78,061 Effect of dilutive potential common shares from stock options, stock awards and employee stock purchase plan 2,932 — Weighted-average shares outstanding - diluted 79,636 78,061 Net income (loss) per share: Basic $ 0.03 $ — Diluted $ 0.03 $ — The following table presents common shares related to potentially dilutive shares excluded from the calculation of diluted net income (loss) per share as their effect would have been anti-dilutive (in thousands): Three Months Ended March 31, 2021 2020 Stock options, restricted stock units and employee stock purchase rights 67 8,182

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We recorded income tax expense of $0.2 million and $0.3 million for the three months ended March 31, 2021 and 2020, respectively, which primarily consisted of foreign taxes. Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the carrying amounts of existing assets and liabilities in the financial statements and their respective tax bases using tax rates expected to be in effect during the years in which the basis differences reverse. We believe it is more likely than not that our federal and state net deferred tax assets will not be fully realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of our deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. A valuation allowance is recorded for loss carryforwards and other deferred tax assets where it is more likely than not that such deferred tax assets will not be realized. Accordingly, we continue to maintain a valuation allowance against all of our U.S. and certain foreign net deferred tax assets as of March 31, 2021. We will continue to maintain a full valuation allowance against our net federal, state, and certain foreign deferred tax assets until there is sufficient evidence to support the recoverability of our deferred tax assets. We had $4.5 million of unrecognized tax benefits as of March 31, 2021. We do not anticipate a material change to our unrecognized tax benefits over the next twelve months. Unrecognized tax benefits may change during the next twelve months for items that arise in the ordinary course of business. Accrued interest and penalties related to unrecognized tax benefits are recognized as part of our provision for income taxes in our condensed consolidated statements of operations. We are subject to taxation in the United States, various states, and several foreign jurisdictions. Because we have net operating loss and credit carryforwards, there are open statutes of limitations in which federal, state, and foreign taxing authorities may examine our tax returns for all years from 2005 through the current period. We are not currently under examination by any taxing authorities.

Geographic Information

Geographic Information	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Geographic Information	Geographic Information The following table depicts the disaggregation of revenue by geographic region based on the ship to location of our customers and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended March 31, 2021 2020 Americas $ 26,270 $ 25,438 Japan 13,619 17,641 Asia Pacific, excluding Japan 6,335 4,882 EMEA 8,619 5,803 Total revenue $ 54,843 $ 53,764 The following table is a summary of our long-lived assets which include property and equipment, net and operating lease right-of-use assets based on the physical location of the assets (in thousands): March 31, December 31, United States $ 32,211 $ 32,558 Japan 1,274 1,566 Other 1,674 2,004 Total $ 35,159 $ 36,128

Revenue Revenue

Revenue Revenue	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Contract Balances The following table reflects contract balances with customers (in thousands): March 31, December 31, 2020 Accounts receivable, net $ 51,449 $ 51,051 Deferred revenue, current 68,299 65,999 Deferred revenue, non-current 44,920 42,700 We receive payments from customers based upon billing cycles. Invoice payment terms usually range from 30 to 90 days. Accounts receivable are recorded when the right to consideration becomes unconditional. Contract assets include amounts related to our contractual right to consideration for performance obligations not yet billed and are included in prepaid and other current assets in the condensed consolidated balance sheets. The amounts were immaterial as of March 31, 2021 and December 31, 2020. Deferred revenue primarily consists of amounts that have been invoiced but not yet been recognized as revenue and consists of performance obligations pertaining to support and subscription services. We recognized revenue of $23.1 million and $21.3 million during the three months ended March 31, 2021 and 2020, respectively, related to deferred revenues at the beginning of the respective periods. Deferred Contract Acquisition Costs In connection with the adoption of ASC 340-40, we capitalize certain contract acquisition costs consisting of incremental sales commissions incurred to obtain customer contracts. Deferred commissions related to product revenues are recognized upon transfer of control to customers. Deferred commissions related to services revenue are recognized as the related performance obligations are met. Deferred commissions that will be recognized during the succeeding 12-month period are recorded as prepaid expenses and other current assets, and the remaining portion is recorded as other non-current assets. Amortization of deferred commissions is included in sales and marketing expense. Deferred contract acquisition costs were $9.6 million and $9.0 million as of March 31, 2021 and December 31, 2020, respectively. The related amortization amount was $1.7 million and $1.7 million for the three months ended March 31, 2021 and 2020, respectively. We had no impairment loss in relation to the costs capitalized and no asset impairment charges related to contract assets during the three months ended March 31, 2021 and 2020. Remaining Performance Obligations Remaining performance obligations represent contracted revenues that are non-cancellable and have not yet been recognized due to unsatisfied or partially satisfied performance obligations, which include deferred revenues and amounts that will be invoiced and recognized as revenues in future periods. We expect to recognize revenue on the remaining performance obligations as follows (in thousands): March 31, 2021 Within 1 year $ 68,299 Next 2 to 3 years 35,022 Thereafter 9,898 Total $ 113,219

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include those of A10 Networks, Inc. and its subsidiaries after elimination of all intercompany accounts and transactions. We have prepared the accompanying unaudited condensed consolidated financial statements pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC” or the “Commission”). As permitted under these rules and regulations, we have condensed or omitted certain financial information and footnote disclosures we normally include in our annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The unaudited condensed consolidated balance sheet as of December 31, 2020 has been derived from our audited financial statements, which are included in our 2020 Annual Report on Form 10-K for the year ended December 31, 2020 on file with the SEC (the “2020 Annual Report”). These financial statements have been prepared on the same basis as our annual financial statements and, in management’s opinion, reflect all adjustments consisting only of normal recurring adjustments that are necessary for a fair presentation of our financial information. Our interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. The beginning and ending balances for treasury stock, at cost, have been reclassified from additional paid-in capital in the condensed consolidated statement of stockholders’ equity for the three months ended March 31, 2020 to conform with the current year presentation for treasury stock, at cost and additional paid-in capital. This reclassification did not have a material impact on the previously reported financial statements. These financial statements and accompanying notes should be read in conjunction with the financial statements and accompanying notes thereto in the 2020 Annual Report.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Those estimates and assumptions affect revenue recognition and deferred revenue, the allowance for doubtful accounts, the sales return reserve, the valuation of inventory, the fair value of marketable securities, contingencies and litigation, accrued liabilities, deferred commissions and the determination of fair value of stock-based compensation. These estimates are based on information available as of the date of the condensed consolidated financial statements.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers Financial instruments that potentially subject us to concentrations of credit risk consist of cash, cash equivalents, marketable securities and accounts receivable. Our cash, cash equivalents and marketable securities are held and invested in high-credit quality financial instruments by recognized financial institutions and are subject to minimum credit risk. Our accounts receivable are unsecured and represent amounts due to us based on contractual obligations of our customers. We mitigate credit risk in respect to accounts receivable by performing periodic credit evaluations based on a number of factors, including past transaction experience, evaluation of credit history and review of the invoicing terms of the contract. We generally do not require our customers to provide collateral to support accounts receivable. Significant customers, including distribution channel partners and direct customers, are those which represent 10% or more of our total revenue for each period presented or our gross accounts receivable balance as of each respective balance sheet date.
Recently Adopted Accounting Guidance/Recent Accounting Pronouncements Not Yet Effective	Recently Adopted Accounting Pronouncements Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), as amended, using a modified retrospective approach, with certain exceptions allowed. The standard amends the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the incurred-loss model with an expected-loss model. This new standard also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than by reducing the carrying amount under the current, other-than-temporary-impairment model. The adoption of ASU 2016-13 did not have a significant impact on the Company’s condensed consolidated financial statements. In January 2017, the Financial Accounting Standards Board (“FASB”) issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350)—Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating the requirement to compare the implied fair value of goodwill with its carrying amount as part of step two of the goodwill impairment test referenced in Accounting Standards Codification (“ASC”) 350, Intangibles - Goodwill and Other (“ASC 350”). As a result, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. However, the impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. In January 2020, the Company adopted ASU 2017-04, and the adoption did not have a material impact on the Company’s condensed consolidated financial statements. Effective January 1, 2020, the Company adopted ASU No. 2018-13, Fair Value Measurement (Topic 820 - Changes to the Disclosure Requirements for the Fair Value Measurement) (“ASU 2018-13”). Under ASU 2018-13, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. The guidance is effective for all entities for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years. The adoption of ASU 2018-13 did not have a significant impact on the Company’s condensed consolidated financial statements. In November 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The amendments in this update improve consistent application of and simplify U.S. GAAP for Topic 740 by clarifying and amending existing guidance for, among other items, intra-period allocation, reporting tax law changes and losses in interim periods, state and local taxes not fully based on income and recognition of deferred tax liability related to certain transactions. There is also new guidance related to consolidated group reporting and tax impacts resulting from business combinations. The guidance is effective for public entities for fiscal years beginning after December 15, 2020 and for interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2021 and the adoption of this guidance did not have a significant impact on the Company’s condensed consolidated financial statements. In October 2020, the FASB issued ASU No. 2020-10, Codification Improvements . The amendments in this ASU improve the consistency of the codification and reorganize the guidance into appropriate sections providing less opportunities for disclosures to be missed. The amendments in this update do not change GAAP and are not expected to result in a significant change in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2020. Early
Deferred Contract Acquisition Costs	Deferred Contract Acquisition Costs In connection with the adoption of ASC 340-40, we capitalize certain contract acquisition costs consisting of incremental sales commissions incurred to obtain customer contracts. Deferred commissions related to product revenues are recognized upon transfer of control to customers. Deferred commissions related to services revenue are recognized as the related performance obligations are met. Deferred commissions that will be recognized during the succeeding 12-month period are recorded as prepaid expenses and other current assets, and the remaining portion is recorded as other non-current assets. Amortization of deferred commissions is included in sales and marketing expense.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Revenue as Percentage of Total Revenue	Three Months Ended March 31, Customers 2021 2020 Customer A (a distribution channel partner) 12% * Customer B (a distribution channel partner) 10% * Customer C (a distribution channel partner) * 17% Customer D (a distribution channel partner) * 16% * represents less than 10% of total revenue

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Assets And Liabilities,	The table below presents the Company’s right-of-use assets and lease liabilities as of March 31, 2021 (in thousands): March 31, 2021 Operating leases Right-of-use assets: Other non-current assets $ 26,936 Total right-of-use assets $ 26,936 Lease liabilities: Accrued liabilities $ 5,181 Other non-current liabilities 22,197 Total operating lease liabilities $ 27,378
Lease Payments	The aggregate future lease payments for non-cancelable operating leases as of March 31, 2021 were as follows (in thousands): Remainder of 2021 $ 4,494 2022 4,817 2023 4,414 2024 4,518 2025 4,625 Thereafter 7,148 Total lease payments 30,016 Less: imputed interest (2,638) Present value of lease liabilities $ 27,378
Lease Costs	Three Months Ended March 31, 2021 2020 Operating lease costs $ 1,373 $ 1,777 Short-term lease costs 147 158 Total lease costs $ 1,520 $ 1,935 Average lease terms and discount rates for the Company’s operating leases were as follows: March 31, 2021 Weighted-average remaining term (years) 5.98 Weighted-average discount rate 3.15% Supplemental cash flow information for the Company’s operating leases were as follows (in thousands): Three Months Ended March 31, 2021 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 1,500

Marketable Securities and Fai_2

Marketable Securities and Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Available-for-sale Securities	Marketable securities, classified as available-for-sale, consisted of the following (in thousands): March 31, 2021 December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ — $ — $ — $ — $ 2,150 $ — $ — $ 2,150 Corporate securities 50,477 22 (24) 50,475 45,070 83 (8) 45,145 U.S. Treasury and agency securities 9,496 9 — 9,505 9,493 12 — 9,505 Commercial paper 17,383 — — 17,383 12,136 — — 12,136 Asset-backed securities 7,895 3 — 7,898 5,904 11 — 5,915 Total $ 85,251 $ 34 $ (24) $ 85,261 $ 74,753 $ 106 $ (8) $ 74,851
Schedule of Cost and Estimated Fair Values of Available-for-sale Securities by Contractual Maturity	The following table summarizes the cost and estimated fair value of marketable securities based on stated effective maturities as of March 31, 2021 (in thousands): Amortized Cost Fair Value Less than 1 year $ 76,871 $ 76,887 Mature in 1 - 3 years 8,380 8,374 Total $ 85,251 $ 85,261
Schedule of gross unrealized losses	Marketable securities in an unrealized loss position as of March 31, 2021 consisted of the following (in thousands): Less Than 12 Months 12 Months or More Total As of March 31, 2021 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate securities $ 31,863 $ (18) $ 8,096 $ (6) $ 39,959 $ (24) Marketable securities in an unrealized loss position as of December 31, 2020 consisted of the following (in thousands): Less Than 12 Months 12 Months or More Total As of December 31, 2020 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Corporate securities $ 20,355 $ (8) $ — $ — $ 20,355 $ (8)
Schedule of Cash, Cash Equivalents and Available-for-sale Investments Measured at Fair Value on Recurring Basis	The following is a summary of our cash, cash equivalents and marketable securities measured at fair value on a recurring basis (in thousands): March 31, 2021 December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Cash $ 60,138 $ — $ — $ 60,138 $ 62,388 $ — $ — $ 62,388 Cash equivalents 15,558 — — 15,558 20,893 — — 20,893 Certificates of deposit — — — — — 2,150 — 2,150 Corporate securities — 50,475 — 50,475 — 45,145 — 45,145 U.S. Treasury and agency securities — 9,505 — 9,505 — 9,505 — 9,505 Commercial paper — 17,383 — 17,383 — 12,136 — 12,136 Asset-backed securities — 7,898 — 7,898 — 5,915 — 5,915 Total $ 75,696 $ 85,261 $ — $ 160,957 $ 83,281 $ 74,851 $ — $ 158,132

Condensed Consolidated Financ_2

Condensed Consolidated Financial Statement Details (Tables)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Inventory	Inventory consisted of the following (in thousands): March 31, December 31, Raw materials $ 8,943 $ 8,395 Finished goods 10,604 12,335 Total inventory $ 19,547 $ 20,730
Prepaid Expenses and Other Current Assets		Prepaid expenses and other current assets consisted of the following (in thousands): March 31, December 31, Prepaid expenses $ 4,283 $ 3,818 Deferred contract acquisition costs 5,848 5,345 Other 2,891 3,227 Total prepaid expenses and other current assets $ 13,022 $ 12,390
Schedule of Property and Equipment, Net	Property and equipment, net, consisted of the following (in thousands): Useful Life March 31, December 31, (in years) Equipment 1 - 5 $ 25,875 $ 25,286 Software 1 - 3 765 765 Furniture and fixtures 1 - 7 652 652 Leasehold improvements Lease term 3,616 3,616 Construction in process 2,174 1,677 Property and equipment, gross 33,082 31,996 Less: accumulated depreciation (24,859) (24,108) Property and equipment, net $ 8,223 $ 7,888
Schedule of Acquired Intangible Assets	Purchased intangible assets, net, consisted of the following (in thousands): March 31, 2021 December 31, 2020 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Developed technology $ 5,050 $ (4,797) $ 253 $ 5,050 $ (4,545) $ 505 Patents 2,936 (2,687) 249 2,936 (2,579) 357 Total intangible assets $ 7,986 $ (7,484) $ 502 $ 7,986 $ (7,124) $ 862
Schedule of Future Amortization Expense for Purchased Finite-lived Intangible Assets	Future amortization expense for purchased intangible assets as of March 31, 2021 is as follows (in thousands): Fiscal Year Remainder of 2021 $ 502
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): March 31, December 31, Accrued compensation and benefits $ 11,458 $ 19,725 Accrued tax liabilities 2,030 3,748 Lease liability 5,181 5,260 Other 7,529 8,197 Total accrued liabilities $ 26,198 $ 36,930
Schedule of Deferred Revenue	Deferred revenue consisted of the following (in thousands): March 31, December 31, Deferred revenue: Products $ 6,248 $ 7,358 Services 106,971 101,341 Total deferred revenue 113,219 108,699 Less: current portion (68,299) (65,999) Non-current portion $ 44,920 $ 42,700 The following table reflects contract balances with customers (in thousands): March 31, December 31, 2020 Accounts receivable, net $ 51,449 $ 51,051 Deferred revenue, current 68,299 65,999 Deferred revenue, non-current 44,920 42,700

Equity Incentive Plans and St_2

Equity Incentive Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Summary of Stock-based Compensation	A summary of our stock-based compensation expense is as follows (in thousands): Three Months Ended March 31, 2021 2020 Stock-based compensation by type of award: Stock options $ — $ 110 Stock awards 4,123 2,682 Employee stock purchase rights 276 248 $ 4,399 $ 3,040 Stock-based compensation by category of expense: Cost of revenue $ 572 $ 325 Sales and marketing 1,264 764 Research and development 1,431 1,006 General and administrative 1,132 945 $ 4,399 $ 3,040
Summary of Activity under Stock Option Plans	The following table summarizes our stock option activities and related information: Number of Shares (thousands) Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value (thousands) Outstanding as of December 31, 2020 1,673 $ 5.44 Granted — — Exercised (338) 5.19 Canceled — — Outstanding as of March 31, 2021 1,335 5.51 2.70 $ 5,617 Vested and exercisable as of March 31, 2021 1,335 $ 5.51 2.70 $ 5,617
Summary of Restricted Stock Units Activity	The following table summarizes our stock award activities and related information: Number of Shares (thousands) Weighted-Average Grant Date Fair Value Per Share Weighted-Average Remaining Vesting Term Aggregate Fair Value (thousands) Nonvested as of December 31, 2020 4,888 $ 6.59 Granted 564 9.27 Released (428) 6.67 Canceled (376) 6.57 Nonvested as of March 31, 2021 4,648 $ 6.91 1.74 $ 44,666

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Basic and diluted net income (loss) per share are calculated as follows (in thousands, except per share amounts): Three Months Ended March 31, 2021 2020 Basic and diluted net income (loss) per share Numerator: Net income (loss) $ 2,657 $ (297) Denominator: Weighted-average shares outstanding - basic 76,704 78,061 Effect of dilutive potential common shares from stock options, stock awards and employee stock purchase plan 2,932 — Weighted-average shares outstanding - diluted 79,636 78,061 Net income (loss) per share: Basic $ 0.03 $ — Diluted $ 0.03 $ —
Summary of Anti-dilutive Shares	The following table presents common shares related to potentially dilutive shares excluded from the calculation of diluted net income (loss) per share as their effect would have been anti-dilutive (in thousands): Three Months Ended March 31, 2021 2020 Stock options, restricted stock units and employee stock purchase rights 67 8,182

Geographic Information (Tables)

Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of Total Revenue Based on Customer's Location	The following table depicts the disaggregation of revenue by geographic region based on the ship to location of our customers and is consistent with how we evaluate our financial performance (in thousands): Three Months Ended March 31, 2021 2020 Americas $ 26,270 $ 25,438 Japan 13,619 17,641 Asia Pacific, excluding Japan 6,335 4,882 EMEA 8,619 5,803 Total revenue $ 54,843 $ 53,764
Long-lived Assets by Geographic Areas	The following table is a summary of our long-lived assets which include property and equipment, net and operating lease right-of-use assets based on the physical location of the assets (in thousands): March 31, December 31, United States $ 32,211 $ 32,558 Japan 1,274 1,566 Other 1,674 2,004 Total $ 35,159 $ 36,128

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability	Deferred revenue consisted of the following (in thousands): March 31, December 31, Deferred revenue: Products $ 6,248 $ 7,358 Services 106,971 101,341 Total deferred revenue 113,219 108,699 Less: current portion (68,299) (65,999) Non-current portion $ 44,920 $ 42,700 The following table reflects contract balances with customers (in thousands): March 31, December 31, 2020 Accounts receivable, net $ 51,449 $ 51,051 Deferred revenue, current 68,299 65,999 Deferred revenue, non-current 44,920 42,700
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	We expect to recognize revenue on the remaining performance obligations as follows (in thousands): March 31, 2021 Within 1 year $ 68,299 Next 2 to 3 years 35,022 Thereafter 9,898 Total $ 113,219

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021USD ($)solutionshares	Mar. 31, 2020shares	Mar. 31, 2021USD ($)shares	Dec. 31, 2020shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU asset | $	$ 26,936		$ 26,936
Present value of lease liabilities | $	$ 27,378		$ 27,378
Number of software based advanced solutions | solution	6
Treasury Stock, Shares, Acquired	10,000		2,700,000
Treasury Stock, Shares	5,587,000		5,587,000	5,578,000
Treasury Stock, Value, Acquired, Cost Method | $	$ 88		$ 19,300
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0
Treasury Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Treasury Stock, Shares, Acquired	0	0

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Concentration Risk (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Customer A | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)	12.00%
Customer A | Accounts Receivable
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)	14.00%		17.00%
Customer B | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)	10.00%
Customer B | Accounts Receivable
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)	12.00%		10.00%
Customer C | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)		17.00%
Customer D | Revenue
Entity Wide Revenue Major Customer [Line Items]
Percentage representation of significant customers (percent)		16.00%

Leases - Assets and Liabilities

Leases - Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Total right-of-use assets	$ 26,936
Accrued liabilities	5,181	$ 5,260
Other non-current liabilities	22,197
Total operating lease liabilities	$ 27,378

Leases - Lease Liabilities (Det

Leases - Lease Liabilities (Details) $ in Thousands	Mar. 31, 2021USD ($)
Leases [Abstract]
Remainder of 2021	$ 4,494
2021	4,817
2022	4,414
2023	4,518
2024	4,625
Thereafter	7,148
Total lease payments	30,016
Less: imputed interest	(2,638)
Present value of lease liabilities	$ 27,378

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease costs	$ 1,373	$ 1,777
Short-term lease costs	147	158
Total lease costs	$ 1,520	$ 1,935
Weighted-average remaining term (years)	5 years 11 months 23 days
Weighted-average discount rate	3.15%
Operating cash flows from operating leases	$ 1,500

Marketable Securities and Fai_3

Marketable Securities and Fair Value Measurements - Estimate of Fair Value of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Total	$ 85,251	$ 74,753
Gross Unrealized Gains	34	106
Gross Unrealized Losses	(24)	(8)
Available-for-sale Securities	85,261	74,851
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Total	0	2,150
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Available-for-sale Securities	0	2,150
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Total	50,477	45,070
Gross Unrealized Gains	22	83
Gross Unrealized Losses	(24)	(8)
Available-for-sale Securities	50,475	45,145
U.S. Treasury and agency securities
Debt Securities, Available-for-sale [Line Items]
Total	9,496	9,493
Gross Unrealized Gains	9	12
Gross Unrealized Losses	0	0
Available-for-sale Securities	9,505	9,505
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Total	17,383	12,136
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Available-for-sale Securities	17,383	12,136
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Total	7,895	5,904
Gross Unrealized Gains	3	11
Gross Unrealized Losses	0	0
Available-for-sale Securities	$ 7,898	$ 5,915

Marketable Securities and Fai_4

Marketable Securities and Fair Value Measurements - Contractual Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Amortized Cost
Less than 1 year	$ 76,871
Mature in 1 - 3 years	8,380
Total	85,251	$ 74,753
Fair Value
Less than 1 year	76,887
Mature in 1 - 3 years	8,374
Total	$ 85,261	$ 74,851

Marketable Securities and Fai_5

Marketable Securities and Fair Value Measurements - Securities in Unrealized Loss Position (Details) - Corporate securities - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	$ 31,863	$ 20,355
Fair Value, 12 Months or More	8,096	0
Fair Value, Total	39,959	20,355
Gross Unrealized Losses, Less Than 12 Months	(18)	(8)
Gross Unrealized Losses,12 Months or More	(6)	0
Gross Unrealized Losses, Total	$ (24)	$ (8)

Marketable Securities and Fai_6

Marketable Securities and Fair Value Measurements - Schedule of Fair Value of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial Assets
Marketable Securities	$ 85,261	$ 74,851
Level 1
Financial Assets
Total	75,696	83,281
Level 2
Financial Assets
Total	85,261	74,851
Fair Value, Inputs, Level 1, 2 and 3
Financial Assets
Total	160,957	158,132
Cash
Financial Assets
Cash and Cash Equivalents	60,138	62,388
Cash | Level 1
Financial Assets
Cash and Cash Equivalents	60,138	62,388
Cash equivalents
Financial Assets
Cash and Cash Equivalents	15,558	20,893
Cash equivalents | Level 1
Financial Assets
Cash and Cash Equivalents	15,558	20,893
Certificates of deposit
Financial Assets
Marketable Securities	0	2,150
Certificates of deposit | Level 2
Financial Assets
Marketable Securities	0	2,150
Corporate securities
Financial Assets
Marketable Securities	50,475	45,145
Corporate securities | Level 2
Financial Assets
Marketable Securities	50,475	45,145
U.S. Treasury and agency securities
Financial Assets
Marketable Securities	9,505	9,505
U.S. Treasury and agency securities | Level 2
Financial Assets
Marketable Securities	9,505	9,505
Commercial paper
Financial Assets
Marketable Securities	17,383	12,136
Commercial paper | Level 2
Financial Assets
Marketable Securities	17,383	12,136
Asset-backed securities
Financial Assets
Marketable Securities	7,898	5,915
Asset-backed securities | Level 2
Financial Assets
Marketable Securities	$ 7,898	$ 5,915

Condensed Consolidated Financ_3

Condensed Consolidated Financial Statement Details - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 8,943	$ 8,395
Finished goods	10,604	12,335
Total inventory	$ 19,547	$ 20,730

Condensed Consolidated Financ_4

Condensed Consolidated Financial Statement Details - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Prepaid expenses	$ 4,283	$ 3,818
Deferred contract acquisition costs	5,848	5,345
Other	2,891	3,227
Total prepaid expenses and other current assets	$ 13,022	$ 12,390

Condensed Consolidated Financ_5

Condensed Consolidated Financial Statement Details - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 33,082	$ 31,996
Less: accumulated depreciation	(24,859)	(24,108)
Property and equipment, net	8,223	7,888
Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	25,875	25,286
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	765	765
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	652	652
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,616	3,616
Construction in process
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 2,174	$ 1,677
Minimum | Equipment
Property Plant And Equipment [Line Items]
Useful life	1 year
Minimum | Software
Property Plant And Equipment [Line Items]
Useful life	1 year
Minimum | Furniture and fixtures
Property Plant And Equipment [Line Items]
Useful life	1 year
Minimum | Leasehold improvements
Property Plant And Equipment [Line Items]
Useful life	2 years
Maximum | Equipment
Property Plant And Equipment [Line Items]
Useful life	5 years
Maximum | Software
Property Plant And Equipment [Line Items]
Useful life	3 years
Maximum | Furniture and fixtures
Property Plant And Equipment [Line Items]
Useful life	7 years
Maximum | Leasehold improvements
Property Plant And Equipment [Line Items]
Useful life	8 years

Condensed Consolidated Financ_6

Condensed Consolidated Financial Statement Details - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.7	$ 1.3
Amortization expense related to intangible assets	$ 0.4	$ 0.4

Condensed Consolidated Financ_7

Condensed Consolidated Financial Statement Details - Purchased Intangible Assets, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 7,986		$ 7,986
Accumulated Amortization	(7,484)		(7,124)
Net	502		862
Amortization expense related to intangible assets	400	$ 400
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	5,050		5,050
Accumulated Amortization	(4,797)		(4,545)
Net	253		505
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	2,936		2,936
Accumulated Amortization	(2,687)		(2,579)
Net	$ 249		$ 357

Condensed Consolidated Financ_8

Condensed Consolidated Financial Statement Details - Future Amortization Expense of Acquired Intangibles (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Remainder of 2021	$ 502
Net	$ 502	$ 862

Condensed Consolidated Financ_9

Condensed Consolidated Financial Statement Details - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 11,458	$ 19,725
Accrued tax liabilities	2,030	3,748
Lease liability	5,181	5,260
Other	7,529	8,197
Total accrued liabilities	$ 26,198	$ 36,930

Condensed Consolidated Finan_10

Condensed Consolidated Financial Statement Details - Schedule of Deferred Revenue (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$ 113,219	$ 108,699
Less: current portion	(68,299)	(65,999)
Non-current portion	44,920	42,700
Products
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	6,248	7,358
Services
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$ 106,971	$ 101,341

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 1.4	$ 1.6

Equity Incentive Plans and St_3

Equity Incentive Plans and Stock-Based Compensation - 2014 Equity Incentive Plan/ESPP (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 10, 2015	Oct. 31, 2018	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised				$ 1.5	$ 1.2
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grant (in shares)				10,537,636
2014 Stock Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding shares of common stock		5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Other Share Increase (Decrease)		8,000,000
2014 Employee Stock Purchase Plan | ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of eligible compensation	15.00%
Offering period	24 months
Amended 2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grant (in shares)				1,821,186
Amended 2014 Employee Stock Purchase Plan | ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of eligible compensation			10.00%
Offering period			6 months

Equity Incentive Plans and St_4

Equity Incentive Plans and Stock-Based Compensation - Schedule of Stock-based Compensation Awards Granted under Stock Option Plan in Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 4,399	$ 3,040
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	572	325
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,264	764
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,431	1,006
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,132	945
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	0	110
Stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	4,123	2,682
Employee stock purchase rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 276	$ 248

Equity Incentive Plans and St_5

Equity Incentive Plans and Stock-Based Compensation - Stock-based Compensation/Stock Repurchase Program (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Share-based Payment Arrangement [Abstract]
Total compensation expense related to unvested awards granted, not yet recognized	$ 23.7
Total compensation expense related to unvested awards granted, not yet recognized weighted-average period for recognition (in years)	2 years 4 months 20 days

Equity Incentive Plans and St_6

Equity Incentive Plans and Stock-Based Compensation - Summary of Activity under Stock Option Plans (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Number of Shares (thousands)
Outstanding options, Beginning balance (in shares)	1,673
Granted (in shares)	0
Exercised (in shares)	(338)
Canceled (in shares)	0
Outstanding options, Ending balance (in shares)	1,335
Vested and exercisable (in shares)	1,335
Weighted-Average Exercise Price Per Share
Beginning balance (in dollars per share)	$ 5.44
Granted (in dollars per share)	0
Exercised (in dollars per share)	5.19
Canceled (in dollars per share)	0
Ending balance (in dollars per share)	5.51
Vested and exercisable at end of period (in dollars per share)	$ 5.51
Weighted-average remaining contractual term (in years)	2 years 8 months 12 days
Weighted average remaining contractual term, Vested and exercisable at end of period (in years)	2 years 8 months 12 days
Aggregate Intrinsic Value	$ 5,617
Aggregate Intrinsic Value, Vested and exercisable at end of period	$ 5,617
Closing price (in dollars per share)	$ 9.61
Intrinsic value of options exercised	$ 1,500	$ 1,200

Equity Incentive Plans and St_7

Equity Incentive Plans and Stock-Based Compensation - Information About Stock Options (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 1.5	$ 1.2

Equity Incentive Plans and St_8

Equity Incentive Plans and Stock-Based Compensation - Summary of RSU activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at end of period (in shares)	4,648,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 44,666
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at beginning of period (in shares)	4,888,000
Granted (in shares)	564,000
Released (in shares)	(428,000)
Canceled (in shares)	(376,000)
Unvested at end of period (in shares)	3,444,533
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested at beginning of period (in dollars per share)	$ 6.59
Granted (in dollars per share)	9.27
Released (in dollars per share)	6.67
Canceled (in dollars per share)	6.57
Unvested at ending of period (in dollars per share)	$ 6.91
Weighted-Average Remaining Vesting Term (years)	1 year 8 months 26 days
Fair value of released awards	$ 4,000	$ 3,400
Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at end of period (in shares)	1,203,286

Equity Incentive Plans and St_9

Equity Incentive Plans and Stock-Based Compensation (Details) - Stock Repurchase Program - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 17, 2020
Share-based Payment Arrangement [Abstract]
Treasury Stock, Shares	5,587,000	5,587,000	5,578,000
Stock Repurchase Program, Authorized Amount				$ 50,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 30,700	$ 30,700
Treasury Stock, Value, Acquired, Cost Method	$ 88	$ 19,300
Treasury Stock, Shares, Acquired	10,000	2,700,000

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Outstanding Shares of Common Stock Equivalents (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share Diluted [Line Items]
Net income (loss)	$ 2,657	$ (297)
Weighted-average shares outstanding - basic (in shares)	76,704	78,061
Weighted Average Number Diluted Shares Outstanding Adjustment	2,932	0
Weighted-average shares outstanding - diluted (in shares)	79,636	78,061
Basic	$ 0.03	$ 0
Diluted	$ 0.03	$ 0
Stock options, restricted stock units and employee stock purchase rights
Earnings Per Share Diluted [Line Items]
Anti-dilutive securities excluded from computation of diluted net income per share	67	8,182

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 184	$ 319
Unrecognized tax benefits	$ 4,500

Geographic Information - Schedu

Geographic Information - Schedule of Total Revenue Based on Customer's Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total revenue	$ 54,843	$ 53,764
Americas
Segment Reporting Information [Line Items]
Total revenue	26,270	25,438
Japan
Segment Reporting Information [Line Items]
Total revenue	13,619	17,641
Asia Pacific, excluding Japan
Segment Reporting Information [Line Items]
Total revenue	6,335	4,882
EMEA
Segment Reporting Information [Line Items]
Total revenue	$ 8,619	$ 5,803

Geographic Information - Long L

Geographic Information - Long Lived Assets By Geographic Area (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 35,159	$ 36,128
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	32,211	32,558
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	1,274	1,566
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,674	$ 2,004

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accumulated deficit	$ 269,592,000		$ 272,249,000
Deferred revenue	113,219,000		108,699,000
Revenue recognized	23,100,000	$ 21,300,000
Asset impairment charges for contract assets	0
Deferred Sales Commissions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred contract acquisition costs	9,600,000		$ 9,000,000
Amortization	1,700,000	$ 1,700,000
Impairment loss of contract acquisition costs	$ 0

Revenue - Contract Balances (De

Revenue - Contract Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 51,449	$ 51,051
Deferred revenue	68,299	65,999
Deferred revenue, non-current	$ 44,920	$ 42,700

Revenue - Remaining Performance

Revenue - Remaining Performance Obligations (Details) $ in Thousands	Mar. 31, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 113,219
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 68,299
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 35,022
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 9,898
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period	4 years