For Douglas Parigian, a Lowell attorney and renowned amateur golf champion, and his golf partner, Eric McPhail, their toughest challenge of 2015 won't come on the links but in a federal courtroom. Both men face insider-trading allegations brought by the Securities and Exchange Commission and the U.S. Attorney's Office, but Stanley Norkunas, Parigian's attorney, said he'll be filing a motion this week to dismiss the charges against his client.