Amyris (Nasdaq: AMRS) shares are on watch Friday following a unusual insider sale/purchase, which was disclosed late Thursday.

According to a Form 4 filing, CEO John Melo sold 200,577 shares of Amyris stock on June 14th at $1.04 per share. This is interesting because the stock closed at $0.50 yesterday and $0.52 on June 14th. Shares were sold in a private transaction.

The buyer of the stock was director and Kleiner Perkins venture capitalist John Doerr, according to a separate filing.

It is unclear if there was a prior arrangement on the stock sale. Shares of AMRS were over a dollar as recently as early May.

Shares of Amyris are flat at $0.50 in early trading.