Quantum-Si said it is laying off about 20% of its workforce as it pushes the launch of its Proteus protein sequencing system to the second quarter of 2027. The company previously targeted early access during the summer and a full commercial launch by year-end, but management attributed the change to the need to add an integrated instrument design cycle. CEO Jeff Hawkins cited execution risk tied to manufacturing repeatability and consistency across internally produced integrated instruments, alongside concerns about yields and success rates. Reagent development remains largely on track, and the company said launch reagent panels may cover 19–20 amino acids rather than the previously planned 18. The shift also reiterates that Proteus represents a move toward an optical-based detection approach intended to scale proteome-scale sequencing, but the immediate impact is a resource reallocation and extended cash runway into late 2028.