Quantum-Si said it is laying off about 20% of its workforce as it pushes back the launch of its Proteus protein sequencing system to the second quarter of 2027. The proteomics company previously targeted early-access availability in summer and a full commercial launch by the end of 2027. Quantum-Si linked the delay primarily to adding an integrated instrument design cycle to reduce manufacturing execution risk. It said the company saw performance variation across internally produced instruments and concluded that moving the current design into production carried too much uncertainty, especially around repeatability, consistency, yields, and success rates. The company also said reagent development remains on track and that reagents capable of detecting 19 or 20 amino acids are likely at launch. Quantum-Si projects the layoffs and cost actions will generate about $12 million in annualized operating expense reductions and extend its cash runway into late 2028.