Common stock (Tables)

12 Months Ended

Dec. 31, 2013

Common stock

Schedule of common stock issued

   During the year ended December 31, 2013, the Company issued 1,378,631 shares of common stock as follows:

Restricted stock grants	860,739
Employee option exercises	304,769
Warrant exercises	213,123
Total common stock issued	1,378,631

       During the year ended December 31, 2012, the Company issued 1,894,452 shares of common stock as follows:

Inter-Atlantic warrant exercise	917,602
Employee option exercises	488,513
Consideration shares upon acquisition of BPS	488,337
Total common stock issued	1,894,452

        During the year ended December 31, 2011 the Company issued 5,695,909 shares of common stock as follows:

April 2011 debt conversion(1)	4,474,776
Restricted stock grant to Philip D. Beck(2)	915,000
Exercise of options and warrants	296,133
Other	10,000
Total common stock issued	5,695,909

(1)

In April 2011, the convertible debt holders converted the outstanding principal amount of $9.0 million under convertible notes issued in 2007 and 2008 into an aggregate of 4,049,776 shares of common stock. In addition, the Company issued 127,318 shares of common stock valued at $0.3 million in lieu of cash payments for accrued interest and 297,682 shares of common stock valued at $0.6 million as a prepayment fee negotiated at the time of conversion. The shares issued for the accrued interest and the prepayment fee were valued at the average closing price of the Company's common stock on AIM under the symbol "PPTR" during the 10 trading day period ending two days prior to the conversion.

(2)

Please Refer to Note 2, Stock-based compensation expense and assumptions, for further information regarding the restricted stock grant to Philip D. Beck.