Lake Street analyst Robert Brown lowered his price target for Capstone Turbine to $5 from $30 saying the company's oil and gas exposure creates risk. Capstone needs to show "rapid progress" on cost reductions as a high debt load makes the rate of improvement critical, Brown tells investors in a post-earnings research note. He believes Capstone is in a "show-me state" as it continues to execute its strategy of re-orienting its business model to increase its services revenue and streamlining its cost structure. The analyst keeps a Buy rating on the shares.