By Kelly Cloonan

PetMed Express said it received and plans to evaluate a revised offer from SilverCape Investments, its largest shareholder, to acquire the company for $3 a share in cash.

The online pet pharmacy said Tuesday it is prepared to engage with SilverCape over the proposal if the firm executes a nondisclosure agreement containing a standstill provision.

PetMed said SilverCape had ultimately been unwilling to execute a nondisclosure agreement containing a standstill provision after months of negotiation over its previous $4-a-share takeover proposal made in December.

PetMed also reiterated that it would consider any credible proposal that it believes could maximize value for stockholders.

SilverCape disclosed its revised offer on Monday. The firm, which owns about 12% of PetMed, said the reduced price reflects what it described as PetMed's continued deterioration, and continues to value the company at a premium to its recent share price.

SilverCape urged PetMed to engage with its revised offer, and said that taking the company private would provide immediate value to shareholders after years of declining share performance. The firm criticized PetMed's performance and accused directors of failing to meaningfully engage with its earlier proposal or run a robust sale process after receiving acquisition interest.

Write to Kelly Cloonan at kelly.cloonan@wsj.com