0000730272 2026-07-28 2026-07-28 false 0000730272 8-K 2026-07-28 REPLIGEN CORP DE 000-14656 04-2729386 41 Seyon Street Waltham MA 02453 (781) 250-0111 false false false false Common Stock, par value $0.01 per share RGEN NASDAQ false