In addition to my last post an investor always needs to consider the competition. Again an excerpt from the filing of a competitor:

 Other Potential Competitors. As we launch our products into the U.S. clinical dermatology market, we can expect competition from major medical imaging companies, such as General Electric Co., Siemens, Phillips Healthcare, Bayer Diagnostics, Olympus Corporation, Carl Zeiss AG and others, each of which manufactures and markets precision medical diagnostic products and could decide to develop or acquire a product or products to compete with our VivaScope confocal imagers. In addition, the telepathology market is intensely competitive and any of the numerous companies are in the telepathology market and may decide to offer products and services that are competitive to our products. Companies active in this space include, among others, General Electric Co., Siemens AG, Philips Healthcare, Virtual Radiologic Corporation, and Apollo Telemedicine

Most competitors have moved into handheld devices but since the Aura has taken so long to reach market it is already antequated. If any of the deep pocketed majors listed above decide to get into this market the small players will get wiped out. Always a risk and why shrewd investors want to see a company perform before giving it lofty valuations.