Aquí el esquema db

CREATE TABLE Products
(
    id          INT NOT NULL AUTO_INCREMENT,
    category_id  INT NOT NULL,
    description VARCHAR(100),
    price       DECIMAL(10, 2) NOT NULL,
    PRIMARY KEY (id),
    FOREIGN KEY (category_id) REFERENCES Categories(id)
) ENGINE = INNODB;

CREATE TABLE Orders
(
    id           INT NOT NULL AUTO_INCREMENT,
    customer_id  INT NOT NULL,
    status       VARCHAR(20) NOT NULL,
    date_created TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (id),
    FOREIGN KEY (customer_id) REFERENCES Customers(id)
) ENGINE = INNODB;

CREATE TABLE OrderDetails
(
    product_id INT NOT NULL,
    order_id   INT NOT NULL,
    quantity   INT NOT NULL,
    subtotal   DECIMAL(10, 2) NOT NULL,
    PRIMARY KEY (product_id, order_id),
    FOREIGN KEY (product_id) REFERENCES Products(id),
    FOREIGN KEY (order_id)   REFERENCES Orders(id)
) ENGINE = INNODB;

Los modelos

@Embeddable
public class OrderDetailPK
{
    private Product product;
    private Order order;

    public OrderDetailPK() {}

    public OrderDetailPK(Product product, Order order)
    {
        this.product = product;
        this.order   = order;
    }
}

public class OrderDetail {
    @EmbeddedId
    private OrderDetailPK id;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="product_id", insertable=false, updatable=false)
    private Product product;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="order_id", insertable=false, updatable=false)
    private Order order;

    private int quantity;
    private double subtotal;

    public OrderDetail() {}

    public OrderDetail(OrderDetailPK id, int quantity, double subtotal)
    {
        this.product  = id.getProduct();
        this.order    = id.getOrder();
        this.quantity = quantity;
        this.subtotal = subtotal;
    }
    // getters, setters
}

public class Product {
    @Id
    private int id;

    private String description;
    private double price;

    @ManyToOne
    @JoinColumn(name="category_id")
    private Category category;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "Products")
    private List<OrderDetail> orderDetail;
}

public class Order {
    @Id
    private int id;

    @ManyToOne
    @JoinColumn(name="customer_id")
    private Customer customer;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "Orders")
    private List<OrderDetail> orderDetail;
}

Y por alguna razón sigo recibiendo el error.

Concrete type "class models.OrderDetail" with application identity does not declare any primary key fields.

¿Podría alguien señalarme dónde está el problema? Gracias