1 2 3 4 UNITED STATES DISTRICT COURT 5 NORTHERN DISTRICT OF CALIFORNIA 6 SAN JOSE DIVISION 7 8 CARL ZEISS X-RAY MICROSCOPY, Case No. 21-cv-01129-EJD

INC.,

9 ORDER GRANTING MOTION FOR Plaintiff, LEAVE TO SERVE SUPPLEMENTAL 10 EXPERT REPORTS v. 11 Re: ECF No. 250

SIGRAY, INC.,

12 Defendant. 13 14 Plaintiff Carl Zeiss X-Ray Microscopy, Inc. (“Zeiss”) brought this patent infringement and 15 trade secret misappropriation case against Sigray, Inc. (“Sigray”). Zeiss alleges that Sigray 16 misappropriated trade secrets generally related to x-ray microscopy and infringes U.S. Patent No. 17 7,057,187 (the “’187 Patent”) and U.S. Patent No. 7,400,704 (“’704 Patent”). Before the Court is 18 Zeiss’s motion for leave to serve supplemental expert reports. Zeiss’s Mot. for Leave to Serve 19 Suppl. Expert Reports (“Mot.”), ECF No. 250. 20 For the reasons stated below, the Court GRANTS Zeiss’s motion for leave. 21 I. BACKGROUND 22 This case was filed more than four years ago on August 21, 2020. ECF No. 1. Zeiss 23 accuses Sigray of selling two types of infringing x-ray microscopes: the Prisma x-ray microscope 24 (the “Prisma Accused Products”) and the TriLambda x-ray microscope (the “TriLambda Accused 25 Products”) (collectively, the “Accused Products”). Zeiss contends that all Accused Products 26 infringe claims 1–6 and 8–12 of the ‘187 Patent, and that the TriLambda Accused Products also 27 infringe claim 17 of that patent. Further, Zeiss contends that the Prisma Accused Products 1 infringe claims 1–7 and 9–15 of the ‘704 Patent. Sigray does not dispute that the Prisma Accused 2 Products infringe claims 1–6 of the ‘704 Patent. See ECF No. 190 at 3. The Court held at 3 summary judgment that the Prisma Accused Products also infringe claims 7 and 9–15 of the ‘704 4 patent, ECF No. 230 at 13–14, and denied Sigray’s motion for reconsideration. ECF No. 256. 5 The Court also held that the Accused Products infringe all asserted claims of the ‘187 Patent. ECF 6 No. 230 at 13. 7 Fact discovery in this case closed on February 16, 2023, and expert discovery closed on 8 July 27, 2023. ECF Nos. 118, 158. 9 On February 13, 2025, Zeiss filed the present motion to serve supplemental expert reports. 10 The motion was fully briefed on February 27, 2025. Sigray’s Opp. to Mot. to Serve Suppl. Expert 11 Reports (“Opp.”), ECF No. 252. The Court took the motion under submission on March 14, 2025. 12 ECF No. 264. 13 II. LEGAL STANDARD 14 Federal Rule of Civil Procedure 26(e) requires a party to supplement its expert reports “in 15 a timely manner if the party learns that in some material respect the disclosure or response is 16 incomplete or incorrect.” Fed. R. Civ. P. 26(e)(1)(A), (e)(2). “[T]he Rule 26(e) duty to 17 supplement . . . does, in fact, extend beyond the discovery cutoff date.” Woods v. Google, Inc., 18 No. C11-01263-EJD (HRL), 2014 WL 1321007, at *4 (N.D. Cal. Mar. 28, 2014); see also 19 Gamevice, Inc. v. Nintendo Co., No. 18-CV-01942-RS (TSH), 2019 WL 5565942, at *2 (N.D. 20 Cal. Oct. 29, 2019); Hernandez v. Polanco Enters., Inc., 19 F. Supp. 3d 918, 933 (N.D. Cal. 21 2013). Such supplementation “must be disclosed by the time the party’s pretrial disclosures under 22 Rule 26(a)(3) are due,” i.e., 30 days before trial, unless the Court orders otherwise. Fed. R. Civ. P. 23 26(e)(2); see also id. at 26(a)(3). When a discovery cut-off deadline is set by the Court’s 24 scheduling order, reopening discovery by modifying that order requires demonstration of good 25 cause. Id. at 16(b)(4). 26 III. DISCUSSION 27 Zeiss served its initial reports on liability and damages on April 18, 2023 and its reply 1 reports on June 9, 2023. Mot. 3–4. After service of those reports, Sigray produced documents 2 that identify additional sales of products that Zeiss claims are Accused Products. Id. Zeiss seeks 3 leave to serve a supplemental expert report from its liability expert, Dr. Gregory Denbeaux, to 4 explain how Sigray’s additional sales infringe for the same reasons as did the earlier sales of 5 Accused Products. Mot. 1. Zeiss also seeks to serve an updated report from its damages expert, 6 Ms. Kimberly Schenk, to account for the sales in her damages calculation. Id. 7 Sigray does not oppose Zeiss’s motion for supplemental expert reports but seeks a broader 8 order also reopening succinct fact and expert discovery to accompany the reports. Opp. 4. This 9 response raises two issues for the Court to determine: (1) whether the Rules permit Zeiss to serve 10 supplemental expert reports in the first instance; and (2) if so, whether good cause exists to reopen 11 discovery regarding the supplemental reports. 12 A. Duty to Serve Supplemental Expert Reports 13 Zeiss argues that Sigray’s recent production of information concerning additional sales of 14 Accused Products constitutes good cause for supplemental expert reports. Mot. 3–5. Zeiss 15 maintains that it needs to update its expert reports to demonstrate that these additional sales also 16 infringe the asserted patents and update its damages calculation accordingly. 17 The Court need not reach the issue of whether Zeiss has demonstrated good cause to 18 modify the Court’s scheduling orders. Federal Rule of Civil Procedure 26(e)(2) provides an 19 alternative procedure by which Zeiss may supplement its experts’ reports. See Holiday Resales, 20 Inc. v. Hartford Cas. Ins. Co., No. 2:07-CV-01321-JLR, 2008 WL 11343449, at *2 (W.D. Wash. 21 Oct. 2, 2008). Rule 26(e)’s duty to supplement expert reports applies even after the close of 22 discovery, thus obviating the need to reopen discovery. See Woods v. Google, Inc., No. C11- 23 01263-EJD (HRL), 2014 WL 1321007, at *4 (N.D. Cal. Mar. 28, 2014) 24 Holiday Resales is instructive. There, the plaintiff moved to reopen discovery so it could 25 update the damages report of its expert to include anticipated damages through a postponed trial 26 date. Id. at *1. Instead of granting that motion, the court took a different tack and found that Rule 27 26(e)(2) required the plaintiff to supplement its damages report. Id. at *2 (“[T]he court need not 1 grant the motion to reopen discovery in order for Holiday to file a supplemental damages report. 2 Rather, pursuant to Federal Rule of Civil Procedure 26(e)(2), Holiday not only may supplement its 3 damages report, but has an obligation to do so.”). In other words, the plaintiff had a duty to 4 supplement its expert report up to the deadline for pretrial disclosures. The same duty applies to 5 Zeiss here. 6 However, Zeiss’s duty to supplement its expert reports is not limitless. The supplemental 7 reports must not be “significantly different from the original reports and, in [e]ffect, alter[] their 8 theories. . . . Nor may a supplemental report contain additional opinions or rationales or seek[] to 9 ‘strengthen’ or ‘deepen’ opinions expressed in the original expert report.” Id. (cleaned up) 10 (alterations in original). “Rather, [s]upplementation under the Rules means correcting 11 inaccuracies, or filling the interstices of an incomplete report based on information that was not 12 available at the time of the initial disclosure.” Luke v. Fam. Care & Urgent Med. Clinics, 323 F. 13 App'x 496, 500 (9th Cir. 2009) (citing Keener v. United States, 181 F.R.D. 639, 640 (D. Mont. 14 1998)) (internal quotations omitted). 15 Here, the limited scope of Zeiss’s proffered supplemental expert reports—to incorporate 16 additional sales of allegedly infringing products since the service of the initial reports—raise no 17 concern. The supplemental reports will merely extend the same logic in the experts’ original 18 reports to the additional sales. Mot. 4 (“Dr. Denbeaux will explain why the new sales infringe 19 under the same theories of infringement that he applied to the earlier Prisma systems, and Ms. 20 Schenk will apply her same lost profits analysis to the new sales to arrive at the new total damages 21 figure.”). Such supplementation is proper. See In re Xyrem (Sodium Oxybate) Antitrust Litig., No. 22 20-MD-02966-RS (SVK), 2024 WL 4789136, at *2 (N.D. Cal. Nov. 14, 2024) (“[T]he proffered 23 supplemental report is not a new legal theory; it is an updated analysis of the impact of sales caps 24 based upon updated sales information produced in May 2024. . . . Accordingly, in consideration of 25 the facts of this case, Rule 26(e) and the relevant case law, . . . Plaintiffs may submit [their] 26 supplemental report.”); ASC Engineered Sols., LLC v. Island Indus., Inc., No. 27 220CV02284JPMCGC, 2021 WL 2941989, at *2 (W.D. Tenn. July 13, 2021) (“Amended or 1 supplemental expert reports are also permitted where the expert is correcting a damages 2 calculation based on information that was not available when the expert prepared the initial report, 3 as long as the expert does not rely on an entirely new legal theory in correcting his 4 supplementation.”). 5 Accordingly, Zeiss may serve its supplemental expert reports. The Court has not yet set 6 trial dates or a deadline for pretrial disclosures, so Rule 26(a)(3)’s 30-day deadline does not 7 circumscribe the date by which Zeiss must serve the supplemental expert reports. The Court 8 directs the parties to the schedule discussed below in the Conclusion. 9 B. Good Cause to Reopen Discovery 10 Sigray does not oppose Zeiss’s supplemental expert reports but argues that they must be 11 accompanied by corresponding fact and expert discovery. Opp. 1. Though Sigray is not the 12 movant here, it is, in effect, moving the Court to reopen discovery through its opposition. 13 A party moving to reopen discovery must show good cause. Fed. R. Civ. P. 16(b)(4). In 14 evaluating good cause, courts consider five factors: “(1) whether trial is imminent, (2) whether the 15 request is opposed, (3) whether the non-moving party would be prejudiced, (4) whether the 16 moving party was diligent in obtaining discovery within the guidelines established by the court, 17 (5) the foreseeability of the need for additional discovery in light of the time allowed for discovery 18 by the district court, and (6) the likelihood that discovery will lead to relevant evidence.” City of 19 Pomona v. SQM N.A. Corp., 866 F.3d 1060, 1066 (9th Cir. 2017) (quoting United States ex rel. 20 Schumer v. Hughes Aircraft Co., 63 F.3d 1512, 1526 (9th Cir. 1996) (vacated on other grounds)). 21 The inquiry “focuses on the reasonable diligence of the moving party.” Noyes v. Kelly Servs., 488 22 F.3d 1163, 1174 n.6 (9th Cir. 2007) (citing Johnson v. Mammoth Recreations, Inc., 975 F.2d 604, 23 609 (9th Cir. 1992)). If the “[moving] party was not diligent, the inquiry should end.” Johnson, 24 975 F.2d at 609. 25 Here, neither party has submitted evidence of any delay by Sigray to obtain expert 26 discovery regarding the additional sales. The parties appear to have at least discussed scheduling 27 depositions of Zeiss’s experts following service of their supplemental reports. See Opp. 1; ECF 1 No. 260-2. However, the same cannot be said of Sigray’s attempts to obtain fact discovery 2 regarding the additional sales. As the Court explains in its order granting Zeiss’s Motion to Strike 3 Late-Disclosed Witnesses, Sigray had the opportunity to disclose customer witnesses to provide 4 testimony concerning the additional sales during the fact discovery period. ECF No. 267. Sigray 5 failed to do so through the close of expert discovery, knowing that Zeiss’s experts had relied on 6 the record at the close of fact discovery in forming their opinions. As such, Sigray has established 7 diligence in obtaining expert discovery regarding the additional sales, but not in obtaining 8 pertinent fact discovery. 9 Other factors weigh in favor of good cause to reopen expert discovery. No trial date has 10 been set. The parties somewhat dispute whether Zeiss has agreed to additional expert discovery 11 regarding the supplemental reports, but taken at its word, Zeiss would not be opposed to further 12 expert discovery limited to the additional sales. Compare Opp. 1 (asserting that Zeiss “has not 13 agreed that it would make its experts available for depositions on [the supplemental] reports”), 14 with ECF No. 260-2 (Zeiss’s Reply in Support of Its Motion to Strike Late-Disclosed Witnesses) 15 at 6 (“Zeiss never refused to agree to additional expert depositions. . . . Nor did Zeiss refuse to 16 agree to supplemental rebuttal reports from Sigray’s experts.”). Finally, Zeiss itself claims that 17 additional expert discovery following service of its supplemental reports would not delay trial, so 18 it would not suffer prejudice. ECF No. 260-2 (Zeiss’s Reply in Support of Its Motion to Strike 19 Late-Disclosed Witnesses) at 3 n.4 (“While Zeiss intends to submit supplemental expert reports . . 20 . those reports do not require delaying trial. Zeiss understands Sigray desire to re-depose Zeiss’s 21 experts, but those depositions will be limited in scope, and the parties can complete them without 22 affecting trial scheduling.”). 23 Good cause appearing, the Court grants Sigray leave to conduct supplemental depositions 24 of Dr. Denbeaux and Ms. Schenk limited to the additional sales in the supplemental expert reports. 25 The Court also grants Sigray leave to serve supplemental rebuttal expert reports on liability and 26 damages limited to the additional sales. 27

IV. CONCLUSION

Zeiss’s motion for leave to serve supplemental expert reports is GRANTED. Zeiss must 2 serve its supplemental reports by April 18, 2025. 3 The Court grants Sigray leave to conduct supplemental depositions of Dr. Gregory 4 Denbeaux and Ms. Kimberly Schenk limited to the new material in Zeiss’s supplemental expert 5 reports. Both depositions must be completed by May 2, 2025. Sigray may serve rebuttal reports 6 by May 16, 2025 and make its experts available for rebuttal depositions to be completed by May 7 30, 2025. Each of Sigray’s and Zeiss’s depositions may not exceed two (2) hours in length. 8 By April 11, 2025, the parties are further ordered to submit a joint status report indicating 9 whether trial beginning at the end of August is feasible given the supplemental expert discovery 10 described in this Order. If so, the report must also include a proposed schedule with deadlines for 11 pretrial briefing. If this timing is not feasible, the report must provide the parties’ updated 12 availability for trial. 13

IT IS SO ORDERED.

Dated: April 1, 2025 15 aeRO.

EDWARD J. DAVILA

United States District Judge

Z 18

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ORDER RE MOT. FOR SUPPL. EXPERT REPORTS