It was not the after hours trades you should focus on but the entire trading. Below this picture shows all trades over 16,000 shares. There was massive accumulation that took place on Friday. Big blocks traded.
Someone is buying. My guess is it's Sanofi as they like taking a position in the companies that partner with them. For instance they have about 20% of Regeneron. In January of 2014 they purchased 13% of a company they purchased. That deal was finalized after the HSR was filled. Are they doing it with MannKind? I bet they have been buying as have the ETF and other institutional investors. At these low prices it's a screaming buy if you have funds. Afrezza will be selling eventually in 120 countries. Sooner or later the share price will explode and leave this penny site behind.