I haven't checked the short interest but BTX has a HUGE number of shares. I think it's something like 65% of the outstanding shares. I can't imagine why, with that much at stake, they would sell shares on the open market. But there was an article on SA talking about them divesting all their holdings.
I think the original selling began in reaction to an AST filing in May re: execution of warrants at $2.34 but the SA article has fueled a panic selling environment. However, this seems to me to be a pretty relevant paragraph from the BTX 6/1 filing (link to filing below):
ITEM 4. PURPOSE OF TRANSACTION The Reporting Person does not have any plans or proposals that relate to or would result in: (a) the acquisition by any person of additional securities of the Company, or the disposition of securities of the Company; (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Company or any of its subsidiaries; (c) a sale or transfer of a material amount of assets of the Company or any of its subsidiaries; (d) any change in the present Board of Directors or management of the Company, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board; (e) any material change in the present capitalization or dividend policy of the Company; (f) any other material change in the Company's business or corporate structure; (g) changes in the Company's charter, bylaws or instruments corresponding thereto or other actions which may impede the acquisition of control of the Company by any person; (h) causing a class of securities of the Company to be delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association; (i) a class of equity securities of the Company becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Exchange Act; or (j) any action similar to any of those enumerated above.>> https://www.etrade.wallst.com/v1/stocks/fundamentals/filing.asp?dockey=168-15901145-6T4AJA1LOC43O24LIVE53IH27I&filingType=SC%2013D&filingDate=06/01/2015&User_SessionID=BC0EE5AFA2F78247E1774F33A1DB9E11