Apparently there were some material issues to be agreed upon before that offer from GaAs Labs was to be accepted to.

The December 30, 2015 Proposed Merger Agreement raises certain material issues that need to be negotiated and resolved with the Excluded Party and there can be no assurance that those issues will be resolved to the satisfaction of the Company's Board of Directors.

Read more: http://www.nasdaq.com/press-release/anadigics-announces-that-a-competing-bidder-has-made-a-further-amended-offer-to-acquire-the-compan-20151231-00293#ixzz3wJgRgoSe