Practice Areas

Our practice focuses on diverse areas of complex civil litigation including intellectual property (patent, trademark and copyright), professional liability, privacy, contract and commercial matters and class actions.

We recognize that different clients have different needs, and we don't take a one-size-fits-all approach. We start every engagement by asking our clients to define what constitutes success for them. The answer to that question allows us to tailor our litigation strategy to our clients’ specific situations. For some clients and cases, the goal may be to win the case – period. For smaller, startup clients facing bet-the-company litigation against bigger, better-funded competitors, the cost of litigation may itself threaten the company’s continued viability. In those situations, we may try to get traction on critical issues at the outset of the case while aggressively containing costs through proactive discovery management. Or we may put more resources into an offensive strategy, targeting a larger opponent’s much larger revenue base. Other clients may simply want to settle as cheaply as possible. In those cases, we try to figure out the pressure points for settlement without getting distracted by expensive side-shows. Our lawyers’ experience allows us to design and execute on this strategic approach to litigation.


We represent companies in patent litigation across the country in cases ranging from biotechnology to e-commerce, solar technology to firewalls. Our clients include Genentech, Google, Twitter, Netflix, Yelp, LinkedIn, Zynga, 23andMe, MobileIron, Fitbit, Infoblox, and Palo Alto Networks.

Our lawyers have extensive patent litigation experience.

Daralyn is trial counsel for Genentech in fending off a string of challenges to Genentech’s Cabilly patent, which generates hundreds of millions in licensing revenue.  She represented Guidewire Software in a bet-the-company case against Accenture Global Services concerning software automating insurance-related tasks. We prevailed at summary judgment on invalidity grounds, an outcome affirmed by the Federal Circuit.  Mark teaches patent law at Stanford, has written seven books and over 100 articles in the field (which have been cited more than 130 times by federal courts, including five times by the U.S. Supreme Court).  In Phillips v. AWH, the reasoning of his amicus brief on behalf of Cisco, Google, IBM, Micron, and Microsoft regarding the proper standards for claim construction was substantially adopted by the en banc Federal Circuit.

Ragesh represented Intel in an inventorship dispute; after a bench trial, the judge rejected his opponent's claims of invention and granted summary judgment on all of plaintiff's state law causes of action. Following a remand, the case resulted in a hung jury and, ultimately, judgment as a matter of law for defendants on all of plaintiff’s state law claims, such that plaintiff received no monetary recovery.  Mike represented Sunlink Corporation, a leading provider of solar power deployment systems, in patent litigation against a much larger competitor.  Having inherited the case after a series of adverse decisions, we turned it around and negotiated an economical business solution to the advantage of both parties.  Mike also represented PixArt in litigation arising out of the settlement of a prior patent case concerning optical tracking technologies (in which we also represented the company).  We resolved that case by negotiating a complex set of patent cross-licenses and crafting an ongoing business relationship between the two former adversaries.

Clem served as lead counsel for Ticketmaster (now Live Nation) in a patent fight against competitor Flash Seats in which we secured a summary judgment victory of both noninfringement and invalidity on five claims. Clem also argued the appeal at the Federal Circuit, which affirmed.  Clem has represented Quantum Corporation in a number of disputes, including a case against Compression Technology Solutions, LLC, in which the district court granted summary judgment on two grounds, finding the patent at issue invalid for failing to claim patentable subject matter and for indefiniteness.  The Federal Circuit affirmed.  Ryan led efforts to win summary judgment of invalidity related to speech recognition technology on behalf of West Interactive and personalization of Internet content on behalf of Yelp.  On behalf of Palo Alto Networks, Ryan was responsible for rulings of summary judgment of non-infringement for two patents and summary judgment of no literal infringement for two other patents, which resulted in an early resolution of the case. In another case for Palo Alto Networks, he won a summary judgment dismissal of trade secrets claims concerning signature scanning algorithms, leading to a walk-away settlement of the remaining patent claims.

Representative matters:

  • OpenTV, Inc. v. Netflix, Inc., 3:14-cv-01723 (N.D. Cal.)
  • Fitbit, Inc. v. Fitbug, Inc., 1:14-cv-01267 (N.D. Ill.)
  • Versata Software Inc. v. Infoblox, Inc., 13-678-LPS (D. Del.)
  • Listingbook LLC v. Market Leader, Inc., 1:13-CV-00583 (M.D.N.C.)
  • E.Digital Corp. v. Eye-Fi, Inc., 3:13-cv-02899 (S.D. Cal.)
  • Airwatch LLC v. Mobile Iron, Inc., 1:12-cv-03571 (N.D. Ga.)
  • Wang v. Palo Alto Networks, 12-cv-05579 (N.D. Cal.)
  • Genetic Technologies Ltd. v. Lab Corp. of America et al., 1:12-cv-01736 (D. Del)
  • Compression Technologies Solutions, LLC v. EMC Corporation et al., 5:12-cv-1746 (N.D. Cal.)
  • DriveCam v. SmartDrive Systems, Inc. Case No. 11CV0997 H RBB (S.D. Cal.)
  • Eastman Kodak Company v. Shutterfly, Inc., Case No. 1:10-cv-01079-SLR (D. Del.)
  • EIT Holdings LLC v. Yelp!, Inc. et al., CV 10 5623 (JCS) (N.D. Cal.)
  • F5 Networks Inc. v. Imperva Inc., 10-cv-00760, (W.D. Wash.)
  • Flash Seats LLC v. Paciolan Inc., 07-cv-00575, (D. Del.)
  • Fortinet, Inc v. Palo Alto Networks, Inc., 09-cv-00036, (N.D. Cal.)
  • Glaxo Group Ltd. v. Genentech, Inc., 09-cv-61608, (C.D. Cal.)
  • Joao Control & Monitoring Systems of California, LLC v. DriveCam, Case No. 8:10-cv-01909-DOC-RNB (C.D. Cal.)
  • Media Queue, LLC v. Netflix, Inc., 2010-1199, (Fed. Cir.)
  • Phoenix Solutions, Inc. v. PG&E, 09-cv-00774, (C.D. Cal.)
  • Phoenix Solutions, Inc. v. West Interactive Corp., 09-cv-08156, (C.D. Cal.)
  • PixArt Imaging, Inc v. Avago Technologies General IP (Singapore) Pte. Ltd., Inc., 10-cv-00544, (N.D. Cal.)
  • Plant Equipment Inc. v. Intrado Inc., 2:09-cv-395 (E.D. Tex.)
  • Ruckus Wireless, Inc. v. Netgear Inc., 09-cv-05271, (N.D. Cal.)
  • Sony Corporation v. Viewsonic Corporation, 09-cv-07698, (C.D. Cal.)
  • Sunpower Corporation, Systems v. Sunlink Corporation, 08-02807, (Cal. Super. Ct. - Alameda County)
  • TQP Development, LLC v. Ticketmaster Entertainment, Inc., 09-cv-00279, (E.D. Tex.)
  • Accenture Global Services, GmbH  v. Guidewire Software, Inc., 07-826 (D. Del.)

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Professional Liability

Durie Tangri attorneys have represented many leading law firms, both Bay Area based and nationwide, in defense of professional liability claims. Our breadth of substantive disciplines and commitment to a "generalist" approach to litigation make us well-suited to step into virtually any professional liability claim, regardless of the underlying field of law. We have defended claims related to patent prosecution and patent litigation, general corporate advice rendered to both start-up and established companies, advice regarding employee benefit plans, and to a wide variety of civil litigation issues.

In addition to defending ripe claims, we frequently are called upon to advise our clients on avoiding or mitigating potential conflict-of-interest issues. Dave, a professor at the University of San Diego School of Law for over ten years, a member of the American Law Institute, and the former co-chair of the San Diego County Bar Association Legal Ethics Committee, focuses on legal ethics and professional liability issues and recently published a legal ethics casebook with Thompson West.

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Durie Tangri attorneys are at the forefront of virtually all of today’s cutting edge Internet privacy cases. The firm was lead counsel in In re Quantcast Advertising Cookie Litigation, a multi-party class action in the Central District of California regarding the “respawning” of http cookies used in behavioral advertising. We represented Google and its AdMob subsidiary in the multidistrict In re iPhone litigation, which combined more than a score of suits alleging improper disclosure and use of personally identifiable information and geolocation data, and achieved full dismissal of all claims.  We currently represent Google in the pending nationwide class action challenging Google’s unified privacy policy, and multiple App developers in the pending iPhone address book nationwide class action.  We represented several parties in the pending Kissmetrics class actions, and are also involved in the pending CarrierIQ privacy class actions.  We represent Twitter in privacy litigation. We also successfully represented Pandora in the Lalo v. Apple and Freeman v. Apple class actions, and in a Flash Cookie privacy class action litigation brought in Arkansas, achieving dismissals in all three cases. And we represented several parties in the In re Facebook Privacy Litigation and In re Zynga Privacy Litigation class actions, which alleged improper disclosure of Facebook user id’s via referrer URLs.

Our extensive experience against the plaintiffs’ bar in these cases, and our close working relationships among the relatively small set of experienced defense counsel in this field, leave us uniquely situated to handle Internet privacy issues in any venue.

Here are some representative engagements:

  • In re Quantcast Advertising Cookie Litigation, 10-cv-05484 (C.D. Cal.)
  • In re Google Inc. Privacy Policy Litigation, 12-cv-01382 (N.D. Cal.)
  • In re Apple iDevice Address Book Litigation, 13-cv-00453 (N.D. Cal.)
  • Lalo v. Apple, Inc., 10-cv-05878 (N.D. Cal.)
  • Freeman v. Apple, Inc., 10-cv-05881 (N.D. Cal.)
  • In re Facebook Privacy Litigation, 10-cv-02389 (N.D. Cal.)
  • In re Zynga Privacy Litigation, 10-cv-04680 (N.D. Cal.)
  • Kimbrough v. Pandora Media, Inc., cv-2011-63-2 (Washington County Circuit Court, Ark.)
  • In re iPhone/iPad Application Consumer Privacy Litigation, 11-md-02250-LHK (JPML/N.D. Cal.)
  • Shively v. CarrierIQ et al., 12-CV-00290-HRL (JPML/N.D. Cal.)
  • Kim v. Kissmetrics et al., 11-cv-03796-LB (N.D. Cal.)

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Contract & Commercial

Durie Tangri lawyers have handled a broad array of complex civil litigation, including disputes relating to contracts, trade secrets, employee mobility, corporate control, and false advertising.

The firm represents the California State University system in class action litigation seeking to roll back fee increases across the entire statewide system. Last year we tried and won a case on behalf of Thomvest Holdings, persuading the court to reform a contract entitling Thomvest to a warrant worth over $11 million.  We are defending the founder of an online social advertising network in a lawsuit brought by an individual who claims to be a co-founder. We filed a lawsuit on behalf of THX, the Lucas Film spin-off, against Monster Cable Products in a dispute over a license agreement. Following a victory on a motion seeking a right to attach Monster's assets the case settled favorably.

The firm's lawyers have represented shareholders in earnout disputes, and venture capital firms and individual board members in disputes over ownership and control of companies, including a trial win for Hummer Winblad Partners in Delaware Chancery Court over control of Napster and the assertion of antitrust claims against the recording industry.  We have litigated a number of cases involving allegations of misappropriation of trade secrets.

Mark wrote the book – literally – on IP and antitrust law. We have represented both plaintiffs and defendants in a wide variety of industries, and in criminal as well as civil antitrust complaints. We also counsel clients on antitrust matters including compliance, amnesty issues, and participation in standard-setting and trade organizations.

Here are some representative engagements:

  • Evans v. Linden Research, Inc., 10-cv-01679 (E.D. Pa.)
  • Halpern v. Shukla, RG 09-466814 (Cal. Super. Ct. - Alameda County)
  • IBM Corp. v. T3 Technologies, Inc., 06-cv-13565 (S.D.N.Y.); 09-4517 (2nd Cir.)
  • PC Specialists, Inc. dba Technology Integration Group v. FusionStorm, CGC 07-464358 (Cal. Super. Ct. - San Francisco County)
  • Phoenix American SalesFocus Solutions, Inc. v. ThomasLloyd Global, CV 085116 (Cal. Super. Ct. - Marin County)
  • Robert J. Thomas v. William James del Biaggio, III et al., Case No. 11-05180-YGR (N.D. Cal.); 11-03191 (N.D. Cal. Bankruptcy Court)
  • Thomas Weisel Partners LLC v. BNP Paribas, 07-cv-06198 (N.D. Cal.)
  • THX Ltd. v. Monster Cable Products, Inc., CIV 1004485 (Cal. Super. Ct. - Marin County)
  • VoIP, Inc. v. Google Inc., BC 418842 (Cal. Super. Ct. - Los Angeles County)
  • Wyde Voice, Free Conferencing v. GIPS, Google, Inc., CGC-12-522868 (Cal. Super. Ct. – San Francisco County)
  • L-7 Designs, Inc. v. Old Navy, LLC, 1:09-cv-01432-DC (S.D.N.Y.)
  • Donselman v. The Board of Trustees of California State University, CGC-09-490977 (Cal. Super. Ct. – San Francisco County)
  • PeopleBrowsr, Inc. et al. v. Twitter, Inc., CGC-12-526393 (Cal. Super. Ct. – San Francisco County)
  • Doe v. Twitter, Inc., CGC-10-503630 (Cal. Super. Ct. – San Francisco)
  • Marcil v. ThomasLloyd Capital LLC, FINRA No. 10-02421
  • Oncology Tech, LLC v. Elekta AB, et al., 5:12-cv-00314 (W.D. Tex.)
  • Shareholder Representative Services v. MEMC Electronic Materials, Inc., 1100074132 (JAMS)
  • Health Line v. Semprus Biosciences, 1:12-cv-00165 (N.D. Utah)
  • Frank Reginald Brown, IV v. Snapchat, Inc., et al., BC5014 (Cal. Super. Ct. – Los Angeles County)
  • Natara Multimedia Group v. Carranza, et al., 1:14-cv-02791 (N.D. Ill.)
  • Zscaler, Inc. v. Anuj Grover, 113cv246711 (Cal. Super. Ct. – Santa Clara County)
  • Filaser v. Kinestral Technologies, Inc., 3:14-cv-00357 (D. of Oregon)
  • Bharadhwaj v. Aryaka Networks, Inc., 1100066245 (JAMS)

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Class Action

Durie Tangri attorneys have extensive experience in defending class action cases, including some of the largest putative classes in the world.  We represent Google in a nationwide class action challenging Google's unification of its various privacy policies, and in an international class action defending against claims of copyright infringement arising from Google's program of scanning works in major library collections.  In the latter, we prevailed on summary judgment, with the court finding that Google's conduct constitutes a fair use of the underlying works.  We represent the California State University system in a class action challenging CSU's response to the California budget crisis.  The court recently denied the Plaintiffs' motion for summary judgment and granted summary adjudication on a key issue in CSU's favor.  We represent multiple application developers in a nationwide class action challenging allegedly improper access to Apple iOS device address books, and have successfully represented Linden Research in defense of two separate class actions challenging the operation of Second Life.  We have successfully defended and settled other class actions, usually at levels below transaction costs, on behalf of clients such as Quantcast, Twitter, Google, and others.

Here are some representative engagements:

  • The Authors Guild v. Google Inc., 05-cv-08136 (S.D.N.Y.)
  • In re Google Inc. Privacy Policy Litigation, 12-cv-01382 (N.D. Cal.)
  • In re Apple iDevice Address Book Litigation, 13-cv-00453 (N.D. Cal.)
  • Doe v. Twitter, Inc., CGC 10-503630 (Cal. Super. Ct.)
  • Donselman v. Board of Trustees of California State University, CGC 09-440977 (Cal. Super. Ct.)
  • Eros, LLC v. Linden Research, Inc., 09-cv-04269 (N.D. Cal.)
  • Evans v. Linden Research, Inc., 10-cv-01679 (E.D. Pa., N.D. Cal.)
  • CLRB Hanson Industries, LLC v. Google Inc., 09-17380 (9th Cir.)
  • Valdez v. Quantcast Corporation, 10-cv-05484 (C.D. Cal.)
  • Greene v. Google Inc., 13-cv-03613 (N.D. Cal)

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Durie Tangri lawyers regularly appear in state and federal appellate courts, especially the Federal Circuit and Ninth Circuit Courts of Appeal.

After obtaining summary judgment in patent cases for clients such as Guidewire, Yelp, and West Interactive Corporation, we continued to advocate for them at the Federal Circuit, which affirmed our district court victories. Mark and Clem represented a group of airlines and online ticket sellers in an appeal to the Federal Circuit, which affirmed a jury verdict in favor of our clients, invalidating a patent for online seat selection. Daralyn and Mark represented insurance software provider Guidewire at the Federal Circuit. The Court affirmed the trial court’s finding that plaintiff’s software patent claimed unpatenable subject matter and were invalid. Joe successfully represented Troy Augusto in a copyright case at the Ninth Circuit, which affirmed summary judgment for our client that the first sale doctrine allowed the resale of promotional music CDs.

Here are some representative engagements:

  • Accenture Global Services, GMBH v. Guidewire Software, Inc., 11-1486 (Fed. Cir.)
  • Kilopass Technology, Inc. v. Sidense Corp., 13-1193 (Fed. Cir.)
  • Adobe Systems Inc. v. Kornrumpf, 12-16616 (9th Cir.)
  • Ceats, Inc. v. Continental Airlines, Inc. et al., 12-1614 (Fed. Cir.)
  • EIT v. Yelp!, Inc., 12-1192 (Fed. Cir.)
  • Phoenix Solutions, Inc. v. West Interactive Corp., 11-1022 (Fed. Cir.)
  • UMG Recordings, Inc. v. Augusto, 08-55998 (9th Cir.)

Companies, non-profits, professional associations, and individuals who stand to be affected by shifts in the law frequently turn to us to draft amicus briefs explaining the broader effects of key rulings. We have submitted amicus briefs to the Second, Third, Seventh, and Ninth Circuit Courts of Appeal, as well as the U.S. Supreme Court on many preeminent recent copyright cases on fair use and first sale.

Representative engagements include:

  • Kirtsaeng v. John Wiley & Sons, 11-697 (2013) (amicus brief for Powell’s Books, Strand Book Store, Half Price Books, and Harvard Book Store)
  • Cariou v. Prince, No. 11-1197 (2d Cir.) (amicus brief for Google)
  • Flava Works, Inc. v. Gunter, 11-3190 (7th Cir.) (amicus brief for Google and Facebook)
  • Viacom Int’l, Inc. v. YouTube, Inc., 10-3270, 10-3342 (2d Cir.) (amicus brief for National Venture Capital Association)
  • Perfect 10, Inc. v. Google, Inc., 10-56316 (9th Cir.) (amicus brief for Chilling Effects Clearinghouse)
  • Murphy v, Millennium Radio Group, LLC, 10-2163 (3d Cir.) (amicus brief for Brave New Films)

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