Image source: Sigma Designs.Shares of semiconductor company Sigma Designs (NASDAQ: SIGM) tumbled on Wednesday following a mixed quarterly report. Sigma beat analyst estimates for earnings but fell short on revenue, leading the stock to drop 31% by 11 a.m. EST.Sigma reported third-quarter revenue of $62.7 million, up 1.9% year over year but about $0.7 million lower than the average analyst estimate.