Why has Amazon.com's paid in capitol go up and what would make their stockholders equity increase

Treasury stock, at cost	(1,837)		(1,837)		(1,837)		(1,837)		(1,837)
	Additional paid-in capital	42,865		33,658		26,791		21,389		17,186
	Accumulated other comprehensive loss	(180)		(986)		(1,035)		(484)		(985)
	Retained earnings	52,551		31,220		19,625		8,636		4,916
	Stockholders equity	93,404		62,060		43,549		27,709		19,285
	Total liabilities and stockholders equity	321,195		225,248		162,648		131,310		83,402